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This document describes changes between tagged Emscripten SDK versions.

Note that version numbers do not necessarily reflect the amount of changes between versions. A version number reflects a release that is known to pass all tests, and versions may be tagged more or less frequently at different times.

Note that there is no ABI compatibility guarantee between versions - the ABI may change, so that we can keep improving and optimizing it. The compiler will automatically invalidate system caches when the version number updates, so that libc etc. are rebuilt for you. You should also rebuild object files and libraries in your project when you upgrade emscripten.

Not all changes are documented here. In particular, new features, user-oriented fixes, options, command-line parameters, breaking ABI changes, deprecations, significant internal modifications and optimizations etc. generally deserve a mention. To examine the full set of changes between versions, you can use git to browse the changes between the tags.

See docs/process.md for more on how version tagging works.

3.1.51 (in development)

  • Support for explicitly targeting the legacy Interet Explorer or EdgeHTML (edge version prior to the chromium-based edge) browsers via -sMIN_EDGE_VERSION/-sMIN_IE_VERSION was removed. (#20881)
  • Emscripten is now more strict about handling unsupported shared library inputs. For example, under the old behaviour if a system shared library such as /usr/lib/libz.so was passed to emscripten it would silently re-write this to -lz, which would then search this a libz in its own sysroot. Now this file is passed though the linker like any other input file and you will see an unknown file type error from the linker (just like you would with the native clang or gcc toolchains). (#20886)
  • Support for explicitly targeting the legacy EdgeHTML browser (edge version prior to the chromium-based edge) via -sMIN_EDGE_VERSION was removed. Using -sLEGACY_VM_SUPPORT should still work if anyone still wanted to target this or any other legacy browser.
  • Breaking change: Using the *glGetProcAddress() family of functions now requires passing a linker flag -sGL_ENABLE_GET_PROC_ADDRESS. This prevents ports of native GL renderers from later accidentally attempting to activate "dormant" features if web browser implementations gain new WebGL extensions in the future, which *glGetProcAddress() is not able to support. (#20802)
  • Added Hi DPI support to GLFW. When enabled, GLFW automatically accounts for the devicePixelRatio browser property and changes the size of the canvas accordingly (including dynamically if the canvas is moved from a 4K screen to a 2K screen and vice-versa). glfwGetFramebufferSize now properly returns the canvas size in pixels, while glfwGetWindowSize returns the canvas size is screen size. By default, this feature is disabled. You can enable it before creating a window by calling glfwWindowHint(GLFW_SCALE_TO_MONITOR, GLFW_TRUE). You can also dynamically change it after the window has been created by calling glfwSetWindowAttrib(window, GLFW_SCALE_TO_MONITOR, GLFW_TRUE). (#20584)
  • Transpilation to support older environments/browsers is now performed by babel rather than closure compiler. This means that folks targeting older browsers (e.g. -sLEGACY_VM_SUPPORT) do not need to ensure their code is closure compliant. (#20879)

3.1.50 - 11/29/23

  • Add a port of mimalloc, a fast and scalable multithreaded allocator. To use it, build with -sMALLOC=mimalloc. (#20651)
  • When compiling, Emscripten will now invoke clang or clang++ depending only on whether emcc or em++ was run. Previously it would determine which to run based on individual file extensions. One side effect of this is that you may now see a clang warning when building .c source files using em++: warning: treating 'c' input as 'c++' when in C++ mode. This also means that the DEFAULT_TO_CXX setting now only applies when linking and not when compiling. (#20712)
  • JavaScript library code can now use the full range of ES6 features and we rely on closure compiler to transpile for ES5 when targetting older browsers. For those that would rather perform transpilation seperately outside of emscripten you can use the -sPOLYFILL=0 setting. (#20700)
  • libcxx, libcxxabi, libunwind, and compiler-rt were updated to LLVM 17.0.4. (#20705, #20707, and #20708)
  • Remove BENCHMARK setting. That has not been used by the benchmark suite for some time now (at least not by default), and is much less useful these days given lazy compilation in VMs (which makes it impossible to truly benchmark execution separately from compilation, which BENCHMARK hoped to do).
  • Update GLFW handling of touch events to avoid sending duplicate mousedown and and mouseup events. Maps touchmove to mousemove events for a single primary touch. (#20805)

3.1.49 - 11/14/23

  • Many MEMORY64 fixes for browser and graphics APIs (#20678)
  • The glfwSetWindowSize function no longer switches to fullscreen when the width/height provided as parameters match the screen size. This behavior now matches the behavior of SDL and glut. In order to switch to fullscreen, the client code should invoke Module.requestFullscreen(...) from a user triggered event otherwise the browser raises an error. (#20600)

3.1.48 - 11/05/23

  • The JS assert function is no longer available in release builds when -sSTRICT is used. This should only affect users with custom JS library code which doesn't use #if ASSERTIONS guards around their assert calls. This behaviour matches that of MINIMAL_RUNTIME. (#20592)
  • The minimum version of node required run the compiler was updated from 10.19 to 16.20. This does not effect the node requirements of the generated JavaScript code. (#20551)
  • A new top-level bootstrap script was added. This script is for emscripten developers and helps take a care of post-checkout tasks such as npm install. If this script needs to be run (e.g. becuase package.json was changed, emcc will exit with an error. (#19736)
  • If exceptions are disabled, using new together with std::nothrow no longer aborts if the allocation fails. Instead nullptr is returned now. This does not change the behavior of regular usage of new.
  • Default MIN_CHROME_VERSION was increased from 75 to 85 and default MIN_FIREFOX_VERSION was increased from 68 to 79 to allow Emscripten to use some ES2021 features for smaller JavaScript code size. (#20549)
  • Emscripten now generates PowerShell wrappers for its CLIs. This allows to sidestep some of the issues with legacy cmd.exe, but developers must explicitly opt-in to running PowerShell scripts in system settings or via the Set-ExecutionPolicy command. (#20416)
  • emscripten::val now supports C++20 co_await operator for JavaScript Promises. (#20420)

3.1.47 - 10/09/23

  • The boost-headers port was updated to v1.83.0.
  • The noExitRuntime global is now a JS library symbol that will only be included as needed. User of noExitRuntime will now need to declare a dependency on it. It will get implicitly included if noExitRuntime is part of INCOMING_MODULE_JS_API. (which it is by default), or it can be added to either DEFAULT_LIBRARY_FUNCS_TO_INCLUDE or noExitRuntime. (#20336)
  • The egl, html5, sdl and webgpu libraries now support basic functionality with -sMEMORY64. (#20276)
  • Value types in emscripten/html5.h that correspond the WebIDL long type are now represented as int rather than long types so that they are 32-bit wide on both wasm32 and wasm64. (#20290)
  • EM_JS and EM_ASM that are present in side module now have their syntax validated at build time. (#20258)
  • MAIN_THREAD_EM_ASM_PTR macro added for code that returns a pointer. This mirrors the existing EM_ASM_PTR. (#20261)
  • Emscripten now implements default POSIX signal handlers. These can terminate or abort the program in response to raise cals. (#20257)
  • emscripten::val now prevents accidental access to the underlying JavaScript value from threads other than its owner. This already didn't work correctly in majority of cases, but now it will throw a clear assertion failure. (#20344)
  • emscripten::val can now be iterated over with a C++ range-based for loop. (#20364)

3.1.46 - 09/15/23

  • The wasmTable global is now a JS library function that will only be included as needed. Code that references wasmTable will no need to declare a dependency on it. It can also be explictly included using -sEXPORTED_RUNTIME_METHODS=wasmTable.
  • libunwind updated to LLVM 16.0.6. (#20088)
  • The --minify=0 commnad line flag will now preserve comments as well as whitespace. This means the resulting output can then be run though closure compiler or some other tool that gives comments semantic meaning. (#20121)
  • -sSTRICT now implies -sINCOMING_MODULE_API=[] which is generally good for code size. If you -sSTRICT you now need to be explicit about the incoming module APIs you are supplying. Users who supply symbols on the incoming module but forget to include them in -sINCOMING_MODULE_API will see an error in debug builds so this change will not generate any silent failures.
  • JS library decorators such as __deps and __async are now type checked so that errors are not silently ignored.
  • The USE_GLFW settings now defaults to 0 rather than 2. This matches other other settings such as USE_SDL that default to 0 these days and also matches the existing behaviour for MINIMAL_RUNTIME and STRICT mode. If you use GLFW you now need to explictly opt into it using -sUSE_GLFW or -lglfw. (#19939)
  • A new settings TABLE_BASE was introduced that can be used to place static function addresses (table slots) at a certain offset. This defaults to 1 which is the previously fixed value. (#20149)
  • Clang's error detection of unused variables -Wunused-variable improved, which may require changes in user code (see #20169).

3.1.45 - 08/23/23

  • The function used to add symbols the JS library has been renamed from mergeInto, to the more specific addToLibrary. This new function does not require the passing of LibraryManager.library as a first argument. The old mergeInto continues to exist for backwards compat.
  • The --log_html option was removed from emrun. This option was already not working with python3.8 or above so we hope is safe to say that nobody was relying on it.

3.1.44 - 07/25/23

  • musl libc updated from v1.2.3 to v1.2.4. (#19812)
  • The EM_LOG_FUNC_PARAMS flag to emscripten_log/emscripten_get_callstack has been deprecated and no longer has any effect. It was based on a long-deprecated JS API. (#19820)
  • The internal read_ and readAsync functions no longer handle data URIs. (Higher-level functions are expected to handle that themselves, before calling.) This only effects builds that use -sSINGLE_FILE or --memory-init-file. (#19792)
  • The asm property of the Module object (which held the raw exports of the wasm module) has been removed. Internally, this is now accessed via the wasmExports global. If necessary, it is possible to export wasmExports on the Module object using -sEXPORTED_RUNTIME_METHODS=wasmExports. (#19816)
  • Embind now supports generating TypeScript definition files using the --embind-emit-tsd <filename> option.

3.1.43 - 07/10/23

  • Handling i64 arguments and return values in JS functions is now much simpler with the new __i53abi decorator. When this is set to true, i64 values are automatically converted to JS numbers (i53) at the JS boundary. Parameters outside of the i53 will show up as NaN in the JS code (#19711)
  • EM_JS functions are now supported in side modules (#19705)

3.1.42 - 06/22/23

  • The default minimum Node version of Emscripten output was bumped from 10.19 to 16.0. To run the output JS in an older version of node, you can use e.g. -sMIN_NODE_VERSION=101900 which will apply the previous minimum version of 10.19.0. (#19192).
  • The log message that emcc will sometime print (for example when auto-building system libraries) can now be completely supressed by running with EMCC_LOGGING=0.
  • Runtime dynamic linking symbols such as dlopen and dlsym will no longer cause a linker error when building without -sMAIN_MODULE. Instead stub functions will be included that fail at runtime. This matches the behaviour of other libc functions that we don't implement. For those that prefer to get a linker error we have the -sALLOW_UNIMPLEMENTED_SYSCALLS settings. (#19527)
  • The modifyFunction helper in parseTools.js was renamed to modifyJSFunction and its callback function no longer takes the name of the function being modified. The name is not relevant for JS library functions and can be safely ignored.
  • JS library functions can now be implemented using ES6 arrow notation, which can save to a few bytes on JS code size. (#19539)

3.1.41 - 06/06/23

  • A new setting (CHECK_NULL_WRITES) was added to disabled the checking of address zero that is normally done when STACK_OVERFLOW_CHECK is enabled. (#19487)
  • compiler-rt updated to LLVM 16. (#19506)
  • libcxx and libcxxabi updated to LLVM 16. (#)

3.1.40 - 05/30/23

  • The _emscripten_out(), _emscripten_err() and _emscripten_dbg() functions declared in emscripten/console.h no longer have the underscore prefix and are now documented. (#19445)

3.1.39 - 05/18/23

  • The JS err() function will now bind to console.error by default rather than console.warning. For debugging/tracing/logging we recommend the dbg() function instead. (#19326)
  • The WASM2C options has been removed. All known users are using upstream wabt these days anyhow.

3.1.38 - 05/10/23

  • The dladdr function will now always return an error rather than filling in dummy values. (#19319)
  • The restriction preventing the use of dynamic linking in combination with -sDYNAMIC_EXECUTION=0 was removed. This restriction was being enforced unnecessarily since dynamic linking has not depended on eval() for a while now.
  • Remove extra code for falling back to long-deprecated BlobBuilder browser API when Blob constructor is missing. This was a fix for an issue that has long been fixed. (#19277)

3.1.37 - 04/26/23

  • The EM_PYTHON_MULTIPROCESSING environment variable no longer has any effect. This was added a temporary fallback but should no longer be needed. (#19224)
  • The old reverse dependency system based on tools/deps_info.py has been removed and the existing __deps entries in JS library files can now be used to express JS-to-native dependencies. As well being more precise, and extensible via user-supplied JS libraries, this also speeds up link times since we no longer need scan linker inputs using llvm-nm. It also completely removes the need for the REVERSE_DEPS settings which has now been deprecated. (#18905)
  • Bump the default minimum Firefox version from 65 to 68 (#19191).
  • Background pthreads no longer prevent a Node.js app from exiting. (#19073)

3.1.36 - 04/16/23

  • The USES_DYNAMIC_ALLOC setting has been deprecated. You can get the same effect from -sMALLOC=none. (#19164)

3.1.35 - 04/03/23

  • The following JavaScript runtime functions were converted to JavaScript library functions:
    • UTF8ArrayToString
    • UTF8ToString
    • stringToUTF8Array
    • stringToUTF8
    • lengthBytesUTF8 If you use any of these functions in your JS code you will now need to include them explictly in one of the following ways:
    • Add them to a __deps entry in your JS library file (with leading $)
    • Add them to DEFAULT_LIBRARY_FUNCS_TO_INCLUDE (with leading $)
    • Add them to EXPORTED_FUNCTIONS (without leading $)
    • Set -sLEGACY_RUNTIME to include all of them at once.
  • FS.loadFilesFromDB and FS.saveFilesToDB were removed. We think it's unlikly there were any users of these functions since there is now a separate IDBFS filesystem for folks that want persistence. (#19049)
  • allocateUTF8 and allocateUTF8OnStack library function moved to library_legacy.js. Prefer the more accurately named stringToNewUTF8 and stringToUTF8OnStack. (#19089)
  • SDL_image port was updated to version 2.6.0.
  • -z arguments are now passed directly to wasm-ld without the need for the -Wl, prefix. This matches the behaviour of both clang and gcc. (#18956)
  • Reverted #18525 which runs the JS pre-processor over files passed via --pre-js and --post-js. It turned out this change caused issue for several folks who had JS files with lines that start with # so can't be run through the pre-processor. If folks want to re-enable this we can looks into ways to make it conditional/optional.
  • The {{{ cDefine('name') }}} helper macro can now be simplified to just {{{ cDefs.name }}}.

3.1.34 - 03/14/23

  • Fix for using EM_JS functions defined in other object files. This was a bug that was introduced when LLD_REPORT_UNDEFINED was enabled by default back in 3.1.28. (#18928)
  • The prefered way to enable pthread is now to just the the standard -pthread flag. The -sUSE_PTHREADS setting still works but is marked as legacy and will generate a warning in -sSTRICT mode.
  • When targeting node, and using -sMODULARIZE, we no longer internally catch unhandled promise rejections or exit status code. That is to say the, NODEJS_CATCH_REJECTION and NODEJS_CATCH_EXIT are no longer compatible with -sMODULARIZE.

3.1.33 - 03/08/23

  • Initial support for C++20 modules. We have added a very simple test in form of other.test_cpp_module. (#18915)
  • Removed sys/sysctl.h compatibility header. We don't implement the function it defines. (#18863)
  • Update SDL2_ttf port to 2.20.2 (#18804)
  • Update glfw header to 3.3.8 (#18826)
  • The LLD_REPORT_UNDEFINED setting has been removed. It's now essentially always enabled. (#18342)
  • Added -sEXPORT_KEEPALIVE to export symbols. When using MINIMAL_RUNTIME, the option will be disabled by default. This option simply exports the symbols on the module object, i.e., Module['X'] = X;
  • The WasmFS OPFS backend is now faster in browsers that implement Atomics.waitAsync. (#18861)
  • The emscripten_proxy_async_with_callback API was replaced with a simpler emscripten_proxy_callback API that takes a second callback to be called if the worker thread dies before completing the proxied work.

3.1.32 - 02/17/23

  • Added new linker option -sEXCEPTION_STACK_TRACES which will display a stack trace when an uncaught exception occurs. This defaults to true when ASSERTIONS is enabled. This option is mainly for the users who want only exceptions' stack traces without turning ASSERTIONS on. (#18642 and #18535)
  • SUPPORT_LONGJMP's default value now depends on the exception mode. If Wasm EH (-fwasm-exception) is used, it defaults to wasm, and if Emscripten EH (-sDISABLE_EXCEPTION_CATCHING=0) is used or no exception support is used, it defaults to emscripten. Previously it always defaulted to emscripten, so when a user specified -fwasm-exceptions, it resulted in Wasm EH + Emscripten SjLj, the combination we do not intend to support for the long term.
  • Added support for Wasm-based AudioWorklets for realtime audio processing (#16449)
  • Synchronous proxying functions in emscripten/proxying.h now return errors instead of hanging forever when the worker thread dies before the proxied work is finished.

3.1.31 - 01/26/23

  • Symbols that were previously exported from native code, but only for internal reasons, are no longer exported on the Module object by default. For example, previously if you were using Module._malloc but not explicitly including _malloc in EXPORTED_FUNCTIONS, it might have been exported anyway due to internal use of malloc within the JS library code. (#18564)
  • The STACK_SIZE, STACK_ALIGN, POINTER_SIZE, and ASSERTIONS JavaScript globals were removed by default. In debug builds a clear error is shown if you try to use these. (#18503)
  • --pre-js and --post-js files are now fed through the JS preprocessor, just like JS library files and the core runtime JS files. This means they can now contain #if/#else/#endif blocks and {{{ }}} macro blocks. (#18525)
  • -sEXPORT_ALL can now be used to export symbols on the Module object when used with -sMINIMAL_RUNTIME and -sMODULARIZE together. (#17911)
  • The llvm version that emscripten uses was updated to 17.0.0 trunk.

3.1.30 - 01/11/23

  • The default pthread stack size will now be set to match -sSTACK_SIZE by default. Set DEFAULT_PTHREAD_STACK_SIZE explicitly to override this. (#18479)
  • The buffer JavaScript variable was removed. This underlying buffer is still accessible via wasmMemory.buffer or HEAPXX.buffer. In debug builds, a clear error is shown if you try to use it. (#18454)
  • The SDLv1 header directory is no longer added to the include path by default. This means if you include SDL headers without the explicit version in them (e.g. SDL_events.h) you will now need to add -sUSE_SDL explicitly at compile time. If you include the SDL headers with the directory name included (e.g. SDL/SDL_events.h) you will not be affected by this change. (#18443)
  • Significant improvements were made (in the version of LLVM associated with this emsdk release) to the quality of DWARF debug info when building in optimized mode. See https://reviews.llvm.org/D140373. Using the -O1 flag is recommended if a program is too large or slow to debug with -O0 (although -O0 is still better for debugging when feasible).

3.1.29 - 01/03/23

  • Fixed bug in PROXY_TO_PTHREAD whereby certain async operations on the main thread would cause the whole program to exit, even when the proxied main function was still running. (#18372)
  • Added Module.pthreadPoolReady promise for the PTHREAD_POOL_DELAY_LOAD mode that allows to safely join spawned threads. (#18281)
  • PThreads can now be safely spawned on-demand in Node.js even without a PThread pool (PTHREAD_POOL_SIZE) or proxying (PROXY_TO_PTHREAD) options. (#18305)

3.1.28 - 12/08/22

  • LLD_REPORT_UNDEFINED is now enabled by default. This makes undefined symbol errors more precise by including the name of the object that references the undefined symbol. The old behaviour (of allowing all undefined symbols at wasm-ld time and reporting them later when processing JS library files) is still available using -sLLD_REPORT_UNDEFINED=0. (#16003)
  • musl libc updated from v1.2.2 to v1.2.3. (#18270)
  • The default emscripten config file no longer contains EMSCRIPTEN_ROOT. This setting has long been completely ignored by emscripten itself. For applications that wish to know where emscripten is installed looking for emcc in the PATH has long been the recommended method (i.e. which emcc). (#18279)
  • More accurate synchronisation of emscripten_get_now clocks between main thread and pthreads. This also changes the absolute value returned by the function, but it shouldn't affect correct usages as the function has always returned different values on different platforms, and is clearly documented as "only meaningful in comparison to other calls to this function". (#18267)
  • Emscripten will now search your PATH for binaryen, llvm, and node if the corresponding config file settings (BINARYEN_ROOT, LLVM_ROOT, NODE_JS) are not set. Allows emscripten to run with an empty config file given the right tools in the PATH. (#18289)

3.1.27 - 11/29/22

  • Add support for -sEXPORT_ES6/*.mjs on Node.js. (#17915)
  • Idle workers in a PThread pool no longer prevent Node.js app from exiting. (#18227)
  • The default STACK_SIZE was reduced from 5MB to 64KB. Projects that use more than 64Kb of stack will now need specify -sSTACK_SIZE at link time. For example, -sSTACK_SIZE=5MB can be used to restore the previous behaviour. To aid in debugging, as of #18154, we now also place the stack first in memory in debug builds so that overflows will be immediately detected, and result in runtime errors. This change brings emscripten into line with wasm-ld and wasi-sdk defaults, and also reduces memory usage by default. In general, WebAssembly stack usage should be lower than on other platforms since a lot of state normally stored on the stack is hidden within the runtime and does not occupy linear memory at all. The default for DEFAULT_PTHREAD_STACK_SIZE was also reduced from 2MB to 64KB to match.
  • Improved error messages for writing custom JS libraries. (#18266)
  • EM_ASM code is now supported in side modules (#18228)

3.1.26 - 11/17/22

  • Inline with the recent changes to llvm and binaryen, emscripten will now, by default, enable the sign-extension and mutable-globals WebAssembly proposals. In order to do so the default minimum safari version (MIN_SAFARI_VERSION) was updated from 12.0 to 14.1, and support for the old EdgeHTML engine (MIN_EDGE_VERSION) was removed by default. If you want to continue to support these older engines you can use these settings (-sMIN_SAFARI_VERSION=120000 and/or -sMIN_EDGE_VERSION=44) to revert to the previous defaults, which will result in the new proposals being disabled. Note that in order to avoid support for the sign-extension emscripten uses a binaryen pass, so targeting older browsers requires the running of wasm-opt and is therefore incompatible with ERROR_ON_WASM_CHANGES_AFTER_LINK (i.e. fast linking). (#17690)
  • Added --reproduce command line flag (or equivalently EMCC_REPRODUCE environment variable). This options specifies the name of a tar file into which emscripten will copy all of the input files along with a response file that will allow the command to be replicated. This can be useful for sharing reproduction cases with others (inspired by the lld option of the same name). (#18160)
  • In non-optimizing builds emscripten will now place the stack first in memory, before global data. This is to get more accurate stack overflow errors (since overflow will trap rather corrupting global data first). This should not be a user-visible change (unless your program does something very odd such depending on the specific location of stack data in memory). (#18154)

3.1.25 - 11/08/22

  • The TOTAL_STACK setting was renamed to STACK_SIZE. The old name will continue to work as an alias. (#18128)
  • Exporting print/printErr via -sEXPORTED_RUNTIME_METHODS is deprecated in favor of out/err. The former symbols are supposed to be used with -sINCOMING_MODULE_JS_API instead. (#17955)
  • aio.h was removed from the sysroot. Emscripten doesn't support any of the functions in this header.
  • Clang's function pointer cast warnings (enabled with -Wcast-function-type) are now stricter. This warning is intended to help with CFI errors but also helps wasm builds since wasm traps on such type mismatches in indirect calls. We recommend that users enable it to prevent such errors (which can be hard to debug otherwise). The older (less strict) behavior is also still possible with -Wcast-function-type -Wno-cast-function-type-strict (or -Wno-error=cast-function-type-strict if you want the warnings to be visible but not errors). See https://reviews.llvm.org/D134831
  • libcxx and libcxxabi updated to LLVM 15. (#18113)

3.1.24 - 10/11/22

  • In Wasm exception mode (-fwasm-exceptions), when ASSERTIONS is enabled, uncaught exceptions will display stack traces and what() message. (#17979 and #18003)
  • It is now possible to specify indirect dependencies on JS library functions directly in C/C++ source code. For example, in the case of a EM_JS or EM_ASM JavaScript function that depends on a JS library function. See the EM_JS_DEPS macro in the em_macros.h header. Adding dependencies in this way avoids the need to specify them on the command line with -sDEFAULT_LIBRARY_FUNCS_TO_INCLUDE. (#17854)

3.1.23 - 09/23/22

  • The __EMSCRIPTEN_major__/minor__/tiny__ macros are no longer defined on the command line but require <emscripten.h/> (or just <emscripten/version.h> to be included. (#17883)
  • Linking of bitcode files using emcc -r + -flto is no longer supported. emcc -r will now always use lld to link to an object file. This matches the behavior of upstream llvm where bitcode linking using lld does not exist. The recommend way to combine bitcode input is to use library files (ar archives). See #13492 for more details.

3.1.22 - 09/19/22

  • compiler-rt updated to LLVM 15. (#17802)
  • Using -Oz or -Os will no longer pass -fno-inline-functions to clang and instead rely on clang's normal inline heuristics for these optimization levels. -fno-inline-functions can be passed explicitly if needed.
  • C++17 is now the default version of the C++ standard used by the compiler. This is due to an upstream change in llvm. Use -std=c++14 (or technically -std=gnu++14) to revert to the previous default.
  • Closure warnings are now controlled via the standard -Wclosure warning flags rather than via a specific/custom CLOSURE_WARNINGS setting. The old setting continues to work but will issue a deprecation warning. If you link with -Werror but you don't want closure warnings to be errors you can add -Wno-error=closure or -Wno-closure.

3.1.21 - 09/09/2022

  • Update SDL2 port to 2.24.0 (#17748)
  • The LEGACY_RUNTIME setting is no longer enabled by default. If you use any of these legacy runtime functions (except in library code with explicit dependencies) then you would need to set LEGACY_RUNTIME on the command line or add the ones you need to DEFAULT_LIBRARY_FUNCS_TO_INCLUDE:
    • addFunction
    • removeFunction
    • allocate
    • AsciiToString
    • stringToAscii
    • UTF16ToString
    • stringToUTF16
    • lengthBytesUTF16
    • UTF32ToString
    • stringToUTF32
    • lengthBytesUTF32
    • allocateUTF8
    • allocateUTF8OnStack
    • writeStringToMemory
    • writeArrayToMemory
    • writeAsciiToMemory
    • intArrayFromString
    • intArrayToString
    • warnOnce
    • ccall
    • cwrap Although this is technically a breaking change for those who use these functions, there are assertion in debug builds that catch such usages and direct towards how to fix the issue.

3.1.20 - 08/24/2022

  • The getTempRet0/setTempRet0 helper functions are now implemented directly in WebAssembly, rather than supplied by the JS host. This simplifies the wasm/JS interface. These function are no longer exported in all cases. If your code directly calls these functions from JS, you can add them to -sEXPORTED_RUNTIME_METHODS.
  • Several linux-specific headers were removed from the emscripten sysroot. None of the functionality in these headers was ever supported by emscripten. For example sys/soundcard.h and sys/ptrace.h. (#17704)

3.1.19 - 08/17/2022

  • Old method of metadata extraction via wasm-emscripten-finalize removed in favor of local python code. (#16529)

3.1.18 - 08/01/2022

  • The tests/ directory was renamed to just test/ to match other project close emscripten (llvm, wabt, binaryen). This should not effect any users of emscripten, only developers. (#17502)
  • The llvm version that emscripten uses was updated to 16.0.0 (#17534)
  • worker.js now propagates unhandled promise rejections to the main thread the same way it propagates uncaught exceptions.

3.1.17 - 07/22/2022

  • Add support for dynamic linking with Asyncify. (#15893)
  • A source map file and DWARF info in the wasm can now be emitted at the same if the user gives the both options: -g -gsource-map. (#17484)
  • The align argument to the makeGetValue/makeSetValue JS library macros was removed (and replaced with an assert) as it had no uses internally and was removed (and replaced with an assert) as it had now uses internally and was untested.
  • Removed unused calledMain global variable from the JS runtime. Folks who want to know when main is done can use Module[postRun].

3.1.16 - 07/14/2022

  • Warnings generated by the JS compiler (compiler.js) are now propagated back to the emcc compiler driver which means that -Werror builds will now fail in the presence of JS compiler warnings. As usual -Wno-js-compiler and -Wno-error=js-compiler) can be used to control these warnings. (#17365)
  • When JS library functions are included as part of EXPORTED_RUNTIME_METHODS it is no longer necessary to also add them to DEFAULT_LIBRARY_FUNCS_TO_INCLUDE. This change allows us to transition runtime functions to JS library functions without the need to folks to add DEFAULT_LIBRARY_FUNCS_TO_INCLUDE. (#17369)
  • The following function, which were previously part of the default runtime, are now JS library functions:
    • addFunction
    • removeFunction
    • allocate
    • AsciiToString
    • stringToAscii
    • UTF16ToString
    • stringToUTF16
    • lengthBytesUTF16
    • UTF32ToString
    • stringToUTF32
    • lengthBytesUTF32
    • allocateUTF8
    • allocateUTF8OnStack
    • writeStringToMemory
    • writeArrayToMemory
    • writeAsciiToMemory
    • intArrayFromString
    • intArrayToString
    • warnOnce
    • ccall
    • cwrap However, they all still available by default due to a new setting called LEGACY_RUNTIME which is enabled by default. When LEGACY_RUNTIME is disabled (which it may be in the future) these symbols would only be included if there were explicitly exported via EXPORTED_RUNTIME_METHODS or added to DEFAULT_LIBRARY_FUNCS_TO_INCLUDE. LEGACY_RUNTIME is disabled by default in STRICT mode so this change only effects users of STRICT mode. (#17370, #17403)
  • The run runtime function is no longer exported by default. It can be added to EXPORTED_RUNTIME_METHODS if needed.
  • The getWasmTableEntry/setWasmTableEntry library function are no longer included by default. Add them to DEFAULT_LIBRARY_FUNCS_TO_INCLUDE or EXPORTED_RUNTIME_METHODS if you want to use them outside of JS library code.
  • The type of time_t was restored 64-bit after being converted to 32-bit in 3.1.11. (#17401)

3.1.15 - 07/01/2022

  • The JS library helper function hasExportedFunction has been replaced with hasExportedSymbol, which takes an unmangled (no leading underscore) symbol name.
  • Post-link metadata extraction switched from wasm-emscripten-finalize (binaryen) to python code within emscripten. This change should have no semantic effect, but can temporarily be reverted by setting EMCC_READ_METADATA=binaryen in the environment. (#17337)
  • Added a shim for BigInt64Array so -sWASM_BIGINT can be used in Safari v14. (#17103)

3.1.14 - 06/20/2022

  • emcc now accepts -print-file-name and reports the correct library paths in -print-search-dirs.
  • tools/file_packager no longer generates (or requires) any "pre-js" code when running in --embed-file mode. Instead the embedded files are loaded at static constructor time.
  • Emscripten now knows what minimum browser versions the WASM_BIGINT feature requires and will automatically set the defaults accordingly. (#17163)
  • Embind now supports binding to functions specified as noexcept. (#17140)
  • Weak undefined symbols fixed in dynamic linking. (#17164)
  • Internally, the name of main function now gets mangled (by clang) in the same way as with other wasm targets. This means that within the wasm module the name of the main function can now be __main_argc_argv, but, since we still export this to JS as _main, this should not be a user-visible change.
  • Use of pkg-config from cmake not longer causes the C++ include path to be broken. (#17137)
  • emscripten_runtime_keeplive_push() and emscripten_runtime_keeplive_push() are now exposed to native code and can be used to keep the runtime alive without immediately unwinding the event loop (as emscripten_exit_with_live_runtime() does). (#17160)
  • The file packager option --use-preload-cache now only invalidates the cache if the data contents has changed. (#16807)

3.1.13 - 06/02/2022

  • xlocale.h compatibility header was restored after being removed in 3.1.12.

3.1.12 - 05/25/2022

  • Fix crash, introduced in 3.1.11, which occurred when using pointer types (types ending in *) with getValue/setValue library functions. (#17028)
  • Fix possible deadlock in multi-threaded builds that use EXIT_RUNTIME=0 with ASSERTIONS enabled. This was introduced in 3.1.3 as part of #16130. (#17044)

3.1.11 - 05/21/2022

  • The return value of emscripten_get_compiler_setting was changed from int to long so that it is compatible with MEMORY64. The return value of this function sometimes contains a pointer value so int is not sufficiently wide under wasm64. (#16938)
  • The EM_BUILD_VERBOSE environment variable only effects test code these days and therefore was renamed to EMTEST_BUILD_VERBOSE. (#16904)
  • compiler-rt updated to LLVM 14. (#16991)
  • libc++ updated to LLVM 14. (#17000)
  • libc++abi updated to LLVM 14. (#16993)

3.1.10 - 05/02/2022

  • Bug fixes

3.1.9 - 04/21/2022

  • The -sSHELL_FILE setting, which (unlike the --shell-file command line options) we believe was never tested or externally used, has been removed. (#16589)
  • A warning is now issued when passing C++-only settings such -sEXCEPTION_CATCHING_ALLOWED when not linking as C++. (#16609)
  • Introduce a new proxying API for proxying work between threads.

3.1.8 - 03/24/2022

  • Command line settings (-s) are now type checked. For example, passing a string to a boolean setting will now generate an error (e.g. -sEXIT_RUNTIME=foo). Previously, the value of foo would have have been interpreted as non-zero and accepted as valid. (#16539)
  • A warning (limited-postlink-optimizations) was added that gets shown when binaryen optimizations are limited due to DWARF information being requested. Several binaryen passed are not compatible with the preservation of DWARF information. (#16428)
  • Use normalized mouse wheel delta for GLFW 3 in library_glfw.js. This changes the vertical scroll amount for GLFW 3. (#16480)
  • The emsdk binaries for macOS now require macOS 10.14 Mojave (or above). Prior versions of emsdk could run on 10.11 (or above), but supporting those older versions recently became harder.
  • The SDL_mixer library can be configured to support MIDIs by passing "mid" to the SDL2_MIXER_FORMATS setting. It uses Timidity, and you must provide your own instrument sound files and mount them at "/etc/timidity". (#16556)

3.1.7 - 03/07/2022

  • Remove unmaintained ASMFS filesystem backend and associated -sASMFS settings. The new wasmfs filesystem is far enough along that it seems clear that ASMFS will not need to be revived.
  • Fix deadlock in munmap that was introduced in 3.1.5. The deadlock would occur in multi-threaded programs when a partial unmap was requested (which emscripten does not support). (#16413)
  • Added new compiler+linker option -sSHARED_MEMORY=1, which enables targeting a shared WebAssembly.Memory. (#16419)
  • Added new API "Wasm Workers", which is an alternative to pthreads for building multithreaded applications, enabled via -sWASM_WORKERS=1 (#12833)

3.1.6 - 02/24/2022

  • Remove support for deprecated EMMAKEN_COMPILER, EMMAKEN_CFLAGS, and EMMAKEN_NO_SDK environment variables. These are all legacy and redundant in the face of other settings/flags:
    • EMMAKEN_COMPILER -> LLVM_ROOT in the config settings
    • EMMAKEN_CFLAGS -> EMCC_CFLAGS
    • EMMAKEN_NO_SDK -> standard -nostdlib and -nostdinc flags
  • emscripten will no longer automatically create a config file if it can't find one in the configured location. Instead, it will error out and point the user to the --generate-config option, in case that is what they want. (#13962)

3.1.5 - 02/17/2022

  • Emscripten no longer uses the allocate() runtime function. For backwards compatibility with external JS code we still include this function by default but it will no longer be included in -sSTRICT mode. Usages of this function are generally best replaced with _malloc, stackAlloc or allocateUTF8.

3.1.4 - 02/14/2022

  • Due to an llvm change (https://reviews.llvm.org/D118573) some clang flags that did not previously have any effect are now honored (e.g. -fnew-alignment and -fshort-wchar).
  • llvm dependency updated to 15.0.0 to match upstream. (#16178)
  • The __EMSCRIPTEN_major__, __EMSCRIPTEN_minor__ and __EMSCRIPTEN_tiny__ macros are now available via the emscripten/version.h header file. For the time being, unless you enable -sSTRICT, these are still also defined directly on the command line. If you use these macros please make sure you include emscripten/version.h (or emscripten.h which indirectly includes it). (#16147)

3.1.3 - 01/31/2022

  • The file packager now supports embedding files directly into wasm memory and emcc now uses this mode when the --embed-file option is used. If you use file_packager directly it is recommended that you switch to the new mode by adding --obj-output to the command line. (#16050)
  • The --bind flag used to enable embind has been deprecated in favor of -lembind. The semantics have not changed and the old flag continues to work. (#16087)
  • New setjmp/longjmp support using Wasm EH instructions is added, which is faster and reduces code size. You need a browser that supports Wasm EH spec to use it. The new SjLj support is enabled by -sSUPPORT_LONGJMP=wasm. This can be used with Wasm exception support (-fwasm-exceptions), but not with Emscripten exception support (-fexceptions or -sDISABLE_EXCEPTION_CATCHING=0). When using Wasm EH with Wasm SjLj, there is one restriction that you cannot directly call setjmp within a catch clause. (Calling another function that calls setjmp is fine.) (#14976 and #16072)

3.1.2 - 01/20/2022

  • A new setting, POLYFILL, was added which is on by default but can be disabled (via -sNO_POLYFILL) to prevent emscripten from outputing needed polyfills. For default browser targets, no polyfills are needed so this option only has meaning when targeting older browsers.
  • EVAL_CTORS has been rewritten and improved. The main differences from before are that it is much more capable (it can now eval parts of functions and not just all or nothing, and it can eval more wasm constructs like globals). It is no longer run by default, so to use it you should build with -s EVAL_CTORS. See settings.js for more details. (#16011)
  • wasmX test suites that are defined in test_core.py have been renamed to coreX to better reflect where they are defined. The old suite names such as wasm2 will continue to work for now as aliases.

3.1.1 - 01/08/2022

  • Happy new year!
  • Updated SDL 2 port to upstream version 2.0.18 (from a patched 2.0.10). This includes all downstream patches and many upstream changes.
  • libc++ library updated to llvm-13. (#15901)
  • libc++-abi library updated to llvm-13. (#15904)
  • compiler-rt library updated to llvm-13. (#15906)
  • Added new internal/debugging related environment variable EM_FORCE_RESPONSE_FILES that can be set to 0 to force disable the use of response files, and to 1 to force enable response files. If not set, response files will be used if command lines are long (> 8192 chars). (#15973)

3.1.0 - 12/22/2021

  • Emscripten in starting to use ES6 features in its core libraries (at last!). For most users targeting the default set of browsers this is a code size win. For projects targeting older browsers (e.g. -sMIN_CHROME_VERSION=10), emscripten will now run closure compiler in WHITESPACE_ONLY mode in order to transpile any ES6 down to ES5. When this automatic transpilation is performed we generate a warning which can be disabled (using -Wno-transpile) or by explicitly opting in-to or out-of closure using --closure=1 or --closure=0. (#15763).

3.0.1 - 12/17/2021

  • Deprecate EMMAKEN_CFLAGS is favor of EMCC_CFLAGS.
  • Fixed an issue where user provided --js-library directives would not be processed as the last item after all system provided JS libraries have been added to the build. This fix enables overriding WebGL 2 symbols from user JS libraries.

3.0.0 - 11/22/2021

  • A set of internally-unused functions were removed from parseTools.js. While emscripten no longer needs any of these functions, there is slim chance that some external JS library is depending on them. Please file issues if any such library code is found. The removed/unused functions are: removePointing, pointingLevels, removeAllPointing, isVoidType, isStructPointerType, isArrayType, isStructType, isVectorType, isStructuralType getStructuralTypeParts, getStructuralTypePartBits, isFunctionDef, isPossiblyFunctionType, isFunctionType, getReturnType, splitTokenList, _IntToHex, IEEEUnHex, Compiletime.isPointerType, Compiletime.isStructType, Compiletime.INT_TYPES, isType.
  • The example shell.html and shell_minimal.html templates no longer override printErr on the module object. This means error message from emscripten and stderr from the application will go to the default location of console.warn rather than console.error. This only effects application that use the example shell html files.
  • The version of musl libc used by emscripten was upgraded from v1.1.15 to v1.2.2. There could be some minor size regressions (or gains) due to changes in upstream musl code but we don't expect anything major. Since this is a fairly substantial change (at least internally) we are bumping the major version of Emscripten to 3. (#13006)
  • Added support for specifying the text encoding to be used in response filenames by passing the encoding as a file suffix (e.g. "a.rsp.utf-8" or "a.rsp.cp1252"). If not specified, the encoding is autodetected as either UTF-8 or Python default "locale.getpreferredencoding()". (#15406, #15292, #15426)

2.0.34 - 11/04/2021

  • Symbols marked as visibility hidden are no longer exported from C/C++ code when building with SIDE_MODULE, MAIN_MODULE or LINKABLE. If you need to export a hidden symbol you can still do so by adding it to EXPORTED_FUNCTIONS.

2.0.33 - 11/01/2021

  • Bug fixes

2.0.32 - 10/19/2021

  • Internal-only library functions can now be marked as __internal: true in JS system libraries. Such symbols should not be used by external libraries and are subject to change. As of now we generate warning when external libraries depend on the these symbols.
  • Stub functions from library_syscall.js and library.js were replaced with native code stubs (See system/lib/libc/emscripten_syscall_stubs.c). This should be better for wasm module portability as well as code size. As part of this change the return value of popen was fixed to return NULL rather than -1 and the getpwnam family of functions were changed to return an error rather than throw a JavaScript exception (this behaviour matches what the other stub functions do). As before, the ALLOW_UNIMPLEMENTED_SYSCALLS setting controls whether of not these stubs get included at link time, and STRICT disables this setting.
  • Emscripten will now warn when linker-only flags are specified in compile-only (-c) mode. Just like with clang itself, this warning can be disabled using the flag: -Wno-unused-command-line-argument.
  • Internal symbol names for musl syscalls changed from number-based (e.g. __syscall22) to name-based (e.g. __syscall_open). This should not be a visible change except for folks trying to intercept/implement syscalls in native code (#15202).
  • Fixed launcher batch script issues on Windows, and added two env. vars EM_WORKAROUND_PYTHON_BUG_34780 and EM_WORKAROUND_WIN7_BAD_ERRORLEVEL_BUG that can be enabled to work around a Windows Python issue https://bugs.python.org/issue34780 , and a Windows 7 exit code issue (#15146)
  • Support a new CMake property EMSCRIPTEN_SYSTEM_PROCESSOR which can be used to override the default value of CMAKE_SYSTEM_PROCESSOR set by the toolchain file.
  • Remove support for the EMIT_EMSCRIPTEN_METADATA setting. This setting has been deprecated for some time now and we don't know of any remaining reasons to keep it around.
  • Add JavaScript API Emval.{toHandle, toValue} as well as a C++ method val::as_handle() to allow passing values between the val class and EM_JS/ EM_ASM JavaScript snippets. (#15279)
  • Added SAFE_HEAP=2 option which tests safe heap behavior for wasm-only builds (allowing unaligned memory accesses, which would not work in Wasm2JS but in wasm would be correct but potentially slow).

2.0.31 - 10/01/2021

  • Bug fixes

2.0.30 - 09/14/2021

  • Bug fixes

2.0.29 - 08/26/2021

  • Bug fixes

2.0.28 - 08/23/2021

  • Added some support for signal handling libc functions (raise, kill, sigaction, sigpending, etc). We still don't have a way to deliver signals from the outside but these at least now work for sending signals to the current thread (JS context) (#14883).
  • Remove the workaround used in emcmake and emmake that removed directories with sh.exe from PATH on Windows when MinGW Makefiles generator was used. This was needed with CMake versions older than 3.17.0. If you get an error "sh.exe was found in your PATH" on Windows, you can either update to CMake 3.17.0 or newer, or remove the offending directory from your PATH. See https://github.com/Kitware/CMake/commit/82ddcf0db1d220564145122c3cce25d25ee0e254 for more information. (#14930)

2.0.27 - 08/12/2021

  • Added EM_ASYNC_JS macro - similar to EM_JS, but allows using await inside the JS block and automatically integrates with Asyncify without the need for listing the declared function in ASYNCIFY_IMPORTS (#9709).
  • Errors that occur on pthreads (e.g. uncaught exception) will now get re-thrown on the main thread rather than simply being logged (#13666).

2.0.26 - 07/26/2021

  • When building ports with the embuilder tool some of the names of the libraries have changed (they now match the filenames in the tools/ports/ directory). For example sdl-image is now sdl_image (#14737).
  • Undefined data symbols (in static executables) are no longer silently ignored at link time. The previous behaviour (which was to silently give all undefined data symbols address zero, which could lead to bugs) can be enabled by passing either -Wl,--allow-undefined or -Wl,--unresolved-symbols=ignore-all.
  • The alignment of long double, which is a 128-bit floating-point value implemented in software, is reduced from 16 to 8. The lower alignment allows max_align_t to properly match the alignment we use for malloc, which is 8 (raising malloc's alignment to achieve correctness the other way would come with a performance regression). (#10072)
  • The alignMemory function is now a library function and therefore not included by default. Debug builds will automatically abort if you try to use this function without including it. The normal library __deps mechanism can be used to include it, or can be added to DEFAULT_LIBRARY_FUNCS_TO_INCLUDE.
  • dlopen can now load libraries at runtime from the web without preloading or embedding. This features relies on ASYNCIFY to suspend execution until the library is loaded and then continue on as if dlopen was blocking. For users who don't want to use ASYNCIFY (which has a size and runtime cost) there is a async (callback-based) version of the dlopen API available as emscripten_dlopen() declared in emscropten/emscripten.h. See docs/api_reference/emscripten.h.rst (or the online version) for more details.
  • Constructors, functions and methods bound with Embind can now be awaited. When Asyncify is used somewhere in the callstack, previously Embind would return 0 / null / false / instance with a NULL pointer, making it impossible to wait for the function to actually finish and retrieve its result. Now in those cases it will return a Promise instead that will resolve with the function's return value upon completion. (#11890)

2.0.25 - 06/30/2021

  • Support for the 'shell' environment is now disabled by default. Running under d8, js, or jsc is not something that most emscripten users ever want to do, so including the support code is, more often than not, unnecessary. Users who want shell support can enable it by including 'shell' in -s ENVIRONMENT (#14535).
  • A new setting called ALLOW_UNIMPLEMENTED_SYSCALLS was added. This setting is enabled by default but, if disabled, will generate link-time errors if a program references an unimplemented syscall. This setting is disabled by default in STRICT mode.
  • By default (unless EXIT_RUNTIME=1 is specified) emscripten programs running under node will no longer call process.exit() on exit(). Instead they will simply unwind the stack and return to the event loop, much like they do on the web. In many cases the node process will then exit naturally if there is nothing keeping the event loop going. Note for users of node + pthreads: Because of the way that threads are implemented under node multi-threaded programs now require EXIT_RUNTIME=1 (or call emscripten_force_exit) in order to actually bring down the process.
  • Drop support for node versions older than v5.10.0. We now assume the existence of Buffer.from which was added in v5.10.0. If it turns out there is still a need to support these older node versions we can add a polyfil under LEGACY_VM_SUPPORT (#14447).

2.0.24 - 06/10/2021

  • Support --preload-file in Node.js. (#11785)
  • System libraries are now passed to the linker internally via -lfoo rather than using their full path. This is in line with how gcc and clang pass system libraries to the linker. This should not effect any builds unless a project a happens to have, for example, a file called libc.a in one of its library paths. This would have the effect of overriding the system library (as it would with gcc or clang) (#14342).
  • CMake projects (those that either use emcmake or use Emscripten.cmake directly) are new configured to install (by default) directly into the emscripten sysroot. This means that running cmake --install (or running the install target, via make install for example) will install resources into the sysroot such that they can later be found and used by find_path, find_file, find_package, etc. Previously the default was to attempt to install into the host system (e.g /usr/local) which is almost always not desirable. Folks that were previously using CMAKE_INSTALL_PREFIX to build their own secondary sysroot may be able to simplify their build system by removing this completely and relying on the new default.
  • Reinstated the warning on linker-only -s settings passed when not linking (i.e. when compiling with -c). As before this can disabled with -Wno-unused-command-line-argument (#14182).
  • Standalone wasm mode no longer does extra binaryen work during link. It used to remove unneeded imports, in hopes of avoiding nonstandard imports that could prevent running in WASI VMs, but that has not been needed any more. A minor side effect you might see from this is a larger wasm size in standalone mode when not optimizing (but optimized builds are unaffected). (#14338)
  • You can now explicitly request that an environment variable remain unset by setting its value in ENV to undefined. This is useful for variables, such as LANG, for which Emscripten normally provides a default value.

2.0.23 - 05/26/2021

  • libcxxabi updated to llvm-12. (#14288)
  • libcxx updated to llvm-12. (#14249)
  • compiler-rt updated to llvm-12. (#14280)

2.0.22 - 05/25/2021

  • Fix a crash bug that was present in 2.0.21 with the use of -g. See https://reviews.llvm.org/D102999.
  • wasm-ld will now perform string tail merging in debug string sections as well as regular data sections. This behaviour can be be disabled with -Wl,-O0. This should significantly reduce the size of dwarf debug information in the wasm binary.
  • The experimental SPLIT_MODULE setting now expects the secondary module to be named <module>.deferred.wasm instead of <module>.wasm.deferred.
  • sendfile.h header removed from musl. (#14248)

2.0.21: 05/18/2021

  • Options such as EXPORTED_FUNCTIONS that can take a response file containing list of symbols can now use a simple one-symbol-per-line format. This new format is much simpler and doesn't require commas between symbols, opening or closing braces, or any kind of escaping for special characters.
  • The WebAssembly linker (wasm-ld) now performs string tail merging on any static string data in your program. This has long been part of the native ELF linker and should not be observable in well-behaved programs. This behavior can be disabled by passing -Wl,-O0.
  • The functions fork, vfork, posix_spawn and system now fail with the errno value ENOSYS (52) rather than EAGAIN (6). This is more correct, since they will never work and attempting to retry won't help.
  • EXPORT_ES6 will now emit static URLs for main WebAssembly file as well as for helper Worker used by -pthread that can be statically detected by modern bundlers at build time. In particular, you no longer have to set Module.locateFile hook and Module.mainScriptUrlOrBlob settings - both bundlers and browsers should pick up the required files automatically. Note: this doesn't yet cover other use-cases that emit external files, such as dynamic linking, --proxy-to-worker, external memory etc. (#14135)
  • EXPORT_ES6 can now be used in combination with -o [filename].html. (#14165)
  • EXPORT_ES6 no longer requires setting custom EXPORT_NAME too. (#14139)
  • New diagnostics allow Emscripten to issue warnings when using Intel SIMD intrinsics (from xmmintrin.h) which have slow emulations rather than fast WebAssembly equivalents. To enable them, define WASM_SIMD_COMPAT_SLOW in the preprocessor (#14152)

2.0.20: 05/04/2021

  • This ChangeLog and the emscripten-version.txt file that is checked into the repository now reflect the next, upcoming, release once a release is made. Previously they would continue to reflect the old release until after we decide to cut the release. Switching to this method allow for a slightly simpler release process that also allows us to tag a version that contains the correct version information.
  • The version string reported by -v/--version now includes a -git suffix (e.g. 2.0.19-git) when running from git checkout (to help distinguish unreleased git versions from official releases) (#14092).
  • Temporarily back out new -Wunused-command-line-argument warnings introduced in 2.0.19.

2.0.19: 05/04/2021

  • Emscripten will now warn when linker-only -s settings are specified in compile-only (-c) mode. Just like with clang itself, this warning can be disabled using the flag: -Wno-unused-command-line-argument.
  • When building with -s MAIN_MODULE emscripten will now error on undefined symbol by default. This matches the behvious of clang/gcc/msvc. This requires that your side modules be present on the command line. If you do not specify your side modules on the command line (either direcly or via RUNTIME_LINKED_LIBS) you may need to add -s WARN_ON_UNDEFINED_SYMBOLS=0 to avoid errors about symbol that are missing at link time (but present in your side modules provided at runtime). We hope that this case is not common and most users are building with side modules listed on the command line (#14060).
  • The RUNTIME_LINKED_LIBS setting is now deprecated. It's better to simply list dynamic library dependencies directly on the command line.

2.0.18: 04/23/2021

  • The makeBigInt function was removed from the emscripten runtime since it had no internal users.
  • Restored support for --cache command line flag to configure location of the Emscripten cache root directory.
  • EXTRA_EXPORTED_RUNTIME_METHODS is deprecated in favor of just using EXPORTED_RUNTIME_METHODS.
  • When building with MAIN_MODULE=2 the linker will now automatically include any symbols required by side modules found on the command line. This means that for many users of MAIN_MODULE=2 it should no longer be necessary to list explicit EXPORTED_FUNCTIONS. Also, users of MAIN_MODULE=1 with dynamic linking (not dlopen) who list all side modules on the command line, should be able to switch to MAIN_MODULE=2 and get a reduction in code size.
  • When building with MAIN_MODULE it is now possible to warn or error on undefined symbols assuming all the side modules are passed at link time. This means that for many projects it should now be possible to enable ERROR_ON_UNDEFINED_SYMBOLS along with MAIN_MODULE.

2.0.17: 04/10/2021

  • Use of closure compiler (--closure) is now supported when using dynamic linking (building with -s MAIN_MODULE) (#13880)
  • Specifying EM_CONFIG inline (python code in the environment variable itself) is no longer supported (#13855). This has been long deprecated but finally completely removed.
  • Deprecate -g4, which is a little confusing as it does not do more than -g3 but instead emits source maps instead of DWARF. -g4 will now warn. A new flag -gsource-map enables source maps without warning.
  • In order to behave more like clang and gcc, emscripten no longer supports some nonstandard methods of library lookup (that worked unintentionally and were untested and not documented):
    1. Linking with -llibc rather than -lc will no longer work.
    2. Linking a library called foo.a via -lfoo will no longer work. (libraries found via -l have to start with lib)
  • Use LLVM's new pass manager by default, as LLVM does. This changes a bunch of things about how LLVM optimizes and inlines, so it may cause noticeable changes in compile times, code size, and speed, either for better or for worse. You can use the old pass manager (until LLVM removes it) by passing -flegacy-pass-manager (and -Wl,--lto-legacy-pass-manager when doing LTO) (note however that neither workaround affects the building of system libraries, unless you modify emscripten or build them manually). (#13427)
  • Removed use of Python multiprocessing library because of stability issues. Added a new environment variable EM_PYTHON_MULTIPROCESSING=1 that can be set to revert back to using Python multiprocessing, in case there are reports of regressions (that variable is intended to be temporary). (#13493)
  • Binaryen now always inlines single-use functions. This should reduce code size and improve performance. If you prefer the old default, you can get that with -sBINARYEN_EXTRA_PASSES=--one-caller-inline-max-function-size=1 (#13744).
  • Fix generating of symbol files with --emit-symbol-map for JS targets. When -s WASM=2 is used. Two symbols are generated:
    • [name].js.symbols - storing Wasm mapping
    • [name].wasm.js.symbols - storing JS mapping In other cases a single [name].js.symbols file is created.

2.0.16: 03/25/2021

  • Lists that are passed on the command line can now skip the opening an closing braces, allowing for simpler, more readable settings. e.g. -s EXPORTED_FUNCTIONS=foo,bar
  • Remove/deprecate no longer used --llvm-opts command line option. Any arguments not processed by emcc will be passed through to clang directly these days.
  • Values returned from sysconf now more closely match the definitions found in header files and in upstream musl (#13713).
  • DISABLE_EXCEPTION_CATCHING=2 is now deprecated since it can be inferred from the presence of the EXCEPTION_CATCHING_ALLOWED list. This makes DISABLE_EXCEPTION_CATCHING a simple binary option (0 or 1) which defaults to 0 which will be set to 1 internally if EXCEPTION_CATCHING_ALLOWED list is specified.
  • Values returned from pathconf now match the definitions found in header files and/or upstream musl: _PC_LINK_MAX 3200 -> 8 _PC_SYNC_IO -1 -> 1 _PC_REC_INCR_XFER_SIZE -1 -> 4096 _PC_REC_MAX_XFER_SIZE -1 -> 4096 _PC_SYMLINK_MAX -1 -> 255
  • Added support for wrapping emcc and em++ via ccache: install Emscripten port of ccache via emsdk, or from https://github.com/juj/ccache/tree/emscripten, and run explicitly with "ccache emcc ..." after installing, or automatically just with "emcc ..." after activating ccache via emsdk (#13498).
  • Added support to use a custom set of substitution characters . # and ? to ease passing arrays of C symbols on the command line to ASYNCIFY_* settings. (#13477)
  • In MINIMAL_RUNTIME build mode, errno support will now be disabled by default due to the code size that it adds. (MINIMAL_RUNTIME=1 implies SUPPORT_ERRNO=0 by default) Pass -s SUPPORT_ERRNO=1 to enable errno support if necessary.
  • Using EM_ASM and EM_JS in a side module will now result in an error (since this is not implemented yet). This could effect users were previously inadvertently including (but not actually using) EM_ASM or EM_JS functions in side modules (#13649).
  • Remove dependency on Uglify by finishing the rewrite of passes to acorn (#13636, #13621).
  • Primary development branch switched from master to main.

2.0.15: 03/05/2021

  • Calls to newlocale (and new std::locale in C++) with arbirary names will now succeed. This is the behaviour of musl libc which emscripten had previously inadvertently disabled.
  • System libraries are now compiled with debug info (-g). This doesn't affect release builds (builds without -g) but allows DWARF debugging of types defined in system libraries such as C++ STL types (#13078).
  • uname machine field is now either wasm32 or wasm64 instead of x86-JS (#13440)
  • Several pthreads exit-related fixes (#12985) (#10524).
  • Fix IDBFS syncing with existing directories (#13574).
  • Add libmodplug port and allow mod files to be played in SDL2 (#13478).
  • emscripten_GetProcAddress is now part of libGL. Normally the change is not noticeable, unless you build in STRICT mode and do not already have -lGL to link in that library. If not, add -lGL. (#13524)

2.0.14: 02/14/2021

  • Add new setting: REVERSE_DEPS. This can be used to control how emscripten decides which reverse dependecies to include. See settings.js for more information. The default setting ('auto') is the traditional way emscripten has worked in the past so there should be no change unless this options is actually used. This option partially replaces the EMCC_ONLY_FORCED_STDLIBS environment variable which (among other things) essentially had the effect of setting REVERSE_DEPS to be 'all'.
  • Clang now performs loop unrolling when targeting WebAssembly at -O2 and higher. It can be disabled using -fno-unroll-loops.

2.0.13: 01/19/2021

  • Remove unused Browser.safeSetInterval and Browser.safeCallback. These had no callers in emscripten itself or any testing. If there are users of these functions we could re-enable them with some testing.
  • Fix race condition when running many emcc processes after clearing the cache. The processes would race to run the sanity checks and could interfere with each other (#13299).
  • Emscripten now builds a complete sysroot inside the EM_CACHE directory. This includes the system headers which get copied into place there rather than adding a sequence of extra include directories.
  • Added support for -s MALLOC=emmalloc when -s MAXIMUM_MEMORY is more than 2GB. (#13258)
  • Add back support for calling the legacy dynCall_sig() API to invoke function pointers to wasm functions from JavaScript. Pass -s DYNCALLS=1 to include that functionality in the build. This fixes a regression that started in Aug 31st 2020 (Emscripten 2.0.2) in #12059. Also implement support for dynCall() in MINIMAL_RUNTIME builds. (#13296)
  • SDL2_ttf now uses upstream compiled with TTF_USE_HARFBUZ flag.
  • The system for linking native libraries on demand (based on the symbols present in input object files) has been removed. Libraries such as libgl, libal, and libhtml5 are now included on the link line by default unless -s AUTO_NATIVE_LIBRARIES=0 is used. This should not effect most builds in any way since wasm-ld ignores unreferenced library files. Only users of the --whole-archive linker flag (which is used when MAIN_MODULE=1 is set) should be effected.

2.0.12: 01/09/2021

  • emscripten/vr.h and other remnants of WebVR support removed. (#13210, which is a followup to #10460)
  • Stop overriding CMake default flags based on build type. This will result in builds that are more like CMake does on other platforms. You may notice that RelWithDebInfo will now include debug info (it did not before, which appears to have been an error), and that Release will use -O3 instead of -O2 (which is a better choice anyhow). (#13083)

2.0.11: 12/17/2020

  • emcc -v no longer forces the running the sanity checks. Sanity checks are always run on first use or can be forced with --check or by setting EMCC_DEBUG is set in the environment.
  • An upstream LLVM regression with global initializer linking has been fixed (#13038).
  • Remove a racy unneeded assertion about async dynamic linking (#13060).

2.0.10: 12/04/2020

  • Fix handling of exit() in pthreads. (#12933)
  • Added support for C11 thread API. (#9243)
  • The WebAssembly memory used by emscripten programs is now, by default, created in the wasm file and exported to JavaScript. Previously we could create the memory in JavaScript and import it into the wasm file. The new IMPORTED_MEMORY setting can be used to revert to the old behaviour. Breaking change: This new setting is required if you provide a runtime value for wasmMemory or INITIAL_MEMORY on the Module object.
  • Internally, emscripten now uses the --sysroot argument to point clang at it headers. This should not effect most projects but has a minor effect the order of the system include paths: The root include path (<emscritpen_root>/system/include) is now always last in the include path.
  • Fix JS pthreads proxying + WASM_BIGINT (#12935)
  • Optimize makeDynCall to use dynCall_xx function directly where needed (#12741)

2.0.9: 11/16/2020

  • dlopen, in conformace with the spec, now checks that one of either RTDL_LAZY or RTDL_NOW flags ar set. Previously, it was possible set nether of these without generating an error.
  • Allow -lSDL2_mixer to just work. (Others like -lSDL2 always worked, but for SDL2_mixer things were broken because we build multiple variations of that library.) That link flag is now the same as -s USE_SDL2_MIXER=2.
  • Stack state is no longer stored in JavaScript. The following variables have been replaced with native functions in <emscripten/stack.h>:
    • STACK_BASE
    • STACK_MAX
    • STACKTOP
    • TOTAL_STACK
  • The ABI used for importing symbol by address in dynamic linking (MAIN_MODULE + SIDE_MODULE) is now the same as the ABI used by llvm and wasm-ld. That is, symbol addresses are imported from the 'GOT.mem' and 'GOT.func' pseudo modules. As one side effect of this change it is now required that JavaScript functions that are imported by address are now required to have a __sig specified in the library JavaScript file.
  • MODULARIZE + WASM_ASYNC_COMPILATION=0, that is, modularize mode but with async compilation turned off, so that startup is synchronous, now returns the Module object from the factory function (as it would not make sense to return a Promise without async startup). See #12647
  • Added experimental support for using emscripten as a post link tool. In this case the input to emscripten is a single wasm file (for example the output of wasm-ld). When emcc is run with --post-link it will take a wasm file as input that perform all the normal post link steps such as finalizing and optimizing the wasm file and generating the JavaScript and/or html that will run it.
  • Added emulation support and a build time warning for calling Wasm function pointers from JS library files via the old syntax {{{ makeDynCall('sig') }}} (ptr, arg1, arg2); that was broken on Aug 31st 2020 (Emscripten 2.0.2). A build warning will now be emitted if the old signature is used. Convert to using the new signature {{{ makeDynCall('sig', 'ptr') }}} (arg1, arg2); instead.

2.0.8: 10/24/2020

  • -s ASSERTIONS=2 now implies -s STACK_OVERFLOW_CHECK=2. Previously only -s ASSERTIONS=1 implied -s STACK_OVERFLOW_CHECK=1.
  • Dynamic linking (MAIN_MODULE + SIDE_MODULE) now produces wasm binaries that depend on mutable globals. Specifically the stack pointer global is mutable and shared between the modules. This is an ABI change for dynamic linking. (#12536)
  • emcc now accepts --arg=foo as well as --arg foo. For example --js-library=file.js.
  • Reject promises returned from the factory function created by using the MODULARIZE build option if initialization of the module instance fails (#12396).
  • emrun: Passing command line flags (arguments that start with -) to the program bring run now requires a -- on the command line to signal the end of emrun arguments. e.g: emrun filename.html -- --arg-for-page This is standard behaviour for command line parsing and simplifies the emrun logic.

2.0.7: 10/13/2020

  • Don't run Binaryen postprocessing for Emscripten EH/SjLj. This lets us avoid running wasm-emscripten-finalize just for C++ exceptions or longjmp. This is an ABI change. (#12399)
  • Run SAFE_HEAP on user JS code using a new Acorn pass, increasing the coverage of those tests to all JS in the output (#12450).
  • EM_LOG_DEMANGLE is now deprecated. Function names shown in wasm backtraces are never mangled (they are either missing or demangled already) so demangled is not possible anymore.
  • In STRICT mode we no longer link in C++ mode by default. This means if you are building a C++ program in STRICT mode you need to link via em++ rather than emcc. This matches the behaviour of gcc and clang.
  • IDBFS now persists files whenever their timestamp changes; previously it acted on sync only if the timestamp increased and ignored the file changes otherwise.
  • When -s SUPPORT_LONGJMP=0 is passed to disable longjmp, do not run the LLVM wasm backend path that handles longjmp. Before this only affected linking, and now the flag gives you the ability to affect codegen at compile time too. This is necessary if one does not want any invokes generated for longjmp at all. (#12394)

2.0.6: 10/02/2020

  • Add new COMPILER_WRAPPER settings (with corresponding EM_COMPILER_WRAPPER environment variable. This replaces the existing EMMAKEN_COMPILER environment variable which is deprecated, but still works for the time being. The main differences is that EM_COMPILER_WRAPPER only wrapps the configured version of clang rather than replacing it.
  • ASAN_SHADOW_SIZE is deprecated. When using AddressSanitizer, the correct amount of shadow memory will now be calculated automatically.

2.0.5: 09/28/2020

  • Fix a rare pthreads + exceptions/longjmp race condition (#12056).
  • Add WEBGL_multi_draw_instanced_base_vertex_base_instance bindings (#12282).
  • Fix a rare pthreads main thread deadlock (that worsened in 2.0.2, but existed before). (#12318)
  • The WebAssembly table is now created and exported by the generated wasm module rather then constructed by the JS glue code. This is an implemention detail that should not affect most users, but reduces code size. (#12296)
  • Add getentropy in sys/random.h, and use that from libc++'s random_device. This is more efficient, see #12240.
  • Fixed ABORT_ON_WASM_EXCEPTIONS to work with the recent dynCall changes where functions can be called via the WASM table directly, bypassing WASM exports (#12269).
  • Add ASYNCIFY_ADVISE to output which functions have been instrumented for Asyncify mode, and why they need to be handled. (#12146)

2.0.4: 09/16/2020

  • First release with Bazel support.
  • Stop including malloc and free by default. If you need access to them from JS, you must export them manually using -s EXPORTED_FUNCTIONS=['_malloc', ..].
  • Stop running Binaryen optimizations in -O1. This makes -O1 builds a little larger but they compile a lot faster, which makes more sense in a "compromise" build (in between -O0 and higher optimization levels suitable for release builds). (#12178)
  • Add ERROR_ON_WASM_CHANGES_AFTER_LINK option that errors if we need to do any work in wasm-emscripten-finalize or wasm-opt after linking. This can verify the link is maximally fast and also does no DWARF rewriting. (#12173)

2.0.3: 09/10/2020

  • Breaking changes to calling Wasm function pointers from JavaScript:

    1. It is no longer possible to directly call dynCall_sig(funcPtr, param) to call a function pointer from JavaScript code. As a result, JavaScript code outside all JS libraries (pre-js/post-js/EM_ASM/EM_JS/external JS code) can no longer call a function pointer via static signature matching dynCall_sig, but must instead use the dynamic binding function

      dynCall(sig, ptr, args);

    This carries a significant performance overhead. The function dynCall is not available in -s MINIMAL_RUNTIME=1 builds. 2. old syntax for calling a Wasm function pointer from a JS library file used to be

    {{{ makeDynCall('sig') }}} (ptr, arg1, arg2);
    

    This syntax will no longer work, and until Emscripten <2.0.9 causes a runtime error TypeError: WebAssembly.Table.get(): Argument 0 must be convertible to a valid number.

    New syntax for calling Wasm function pointers from JS library files is

    {{{ makeDynCall('sig', 'ptr') }}} (arg1, arg2);
    

    See PR #12059 for details.

  • The native optimizer and the corresponding config setting (EMSCRIPTEN_NATIVE_OPTIMIZER) have been removed (it was only relevant to asmjs/fastcomp backend).

  • Remove ALLOC_DYNAMIC and deprecate dynamicAlloc. (#12057, which also removes the internal DYNAMICTOP_PTR API.)

  • Add ABORT_ON_WASM_EXCEPTIONS which will abort when an unhandled WASM exception is encountered. This makes the Emscripten program behave more like a native program where the OS would terminate the process and no further code can be executed when an unhandled exception (e.g. out-of-bounds memory access) happens. Once the program aborts any exported function calls will fail with a "program has already aborted" exception to prevent calls into code with a potentially corrupted program state.

  • Use __indirect_function_table as the import name for the table, which is what LLVM does.

  • Remove BINARYEN_SCRIPTS setting.

  • The default output format is now executable JavaScript. Previously we would default to output objecting files unless, for example, the output name ended in .js. This is contrary to behaviour of clang and gcc. Now emscripten will always produce and executable unless the -c, -r or -shared flags are given. This is true even when the name of the output file ends in .o. e.g, emcc foo.c -o foo.o will produce a JavaScript file called foo.o. This might surprise some users (although it matches the behavior of existing toolchains) so we now produce a warning in this case.

2.0.2: 09/02/2020

  • Simplify Fetch C API error handling: we used to check if the error code was 0 and switch that to 404, but that only really helps file:// URLs, which are not very useful for testing anyhow for other reasons (like not working in chrome), and it made things more complex. The behavior has been changed to be simpler and just leave the browser's error code as it is.
  • Enable --no-heap-copy file packager option by default, and remove the old default behavior entirely. That is the behavior we should have had from the beginning as it is more memory-efficient. (#12027)
  • --no-entry is now required in STANDALONE_WASM mode when building a reactor (application without a main function). Previously exporting a list of functions that didn't include _main would imply this. Now the list of EXPORTED_FUNCTIONS is not relevant in the deciding the type of application to build. (#12020)
  • Allow polymorphic types to be used without RTTI when using embind. (#10914)
  • Do not remove __original_main using --inline-main. We used to do this so that it didn't show up in stack traces (which could be confusing because it is added by the linker - it's not in the source code). But this has had several downsides, so we are stopping that now. This does not affect program behavior, unless you look at the wasm internals. However, one noticeable effect is that if you use ASYNCIFY_ADD or ASYNCIFY_ONLY then you may need to add __original_main to there (since you are doing manual fine-tuning of the list of functions, which depends on the wasm's internals). Note that this should not matter in -O2+ anyhow as normal inlining generally removes __original_main. (#11995)

2.0.1: 08/21/2020

  • Change the default value of STACK_OVERFLOW_CHECK in builds with ASSERTIONS from 2 to 1. This means that plain debug builds (-O0, which enables ASSERTIONS) do not have the most expensive stack checks on by default. You can still add them with -s STACK_OVERFLOW_CHECK=2.
  • Remove the RESERVED_FUNCTION_POINTERS setting, which is no longer needed as we have ALLOW_TABLE_GROWTH. The old option allowed a fixed number of functions to be added to the table, while the new one allows an unlimited number. (We needed the old option for fastcomp, which could not support growth.) The old setting is mapped to the new one, so that building with -s RESERVED_FUNCTION_POINTERS=K for any K > 0 will simply turn on table growth. The only noticeable effect of this is that you will be able to add an unlimited amount of functions and not just K.

2.0.0: 08/10/2020

  • First release that only supports the new upstream wasm backend (which has been the default for a long time) and no longer supports the old fastcomp backend. (#11319)
  • Python2 is no longer supported by Emscripten. Emsdk now includes a bundled copy of Python3 on both macOS and Windows. This means that only non-emsdk users and linux users should be affected by this change.
  • Store exceptions metadata in wasm memory instead of JS. This makes exception handling almost 100% thread-safe. (#11518)

1.40.1: 08/01/2020

  • Last release that still has optional support for the old fastcomp backend. The new upstream backend, which has been the default for a long time, will be the only one supported from 2.0.0 and onward (#11319).
  • Fix the WebGL2 regression in 1.40.0 due to #11738 (#11780).
  • If input files don't have a known extension assume they are object files (linker inputs) rather then source files. This matches gcc/clang behaviour. See #10560.

1.40.0: 07/30/2020

  • This release contains a WebGL2 regression due to #11738.
  • The EM_CONFIG environment variable and --em-config command line option no longer support a literal python string. Instead the name of a config file is required. Since all config file settings are individually override-able using EM_FOO this should be enough.
  • Running emscripten under python2 is now deprecated. It will show up as a warning (which can be disabled with -Wno-deprecated). Please update to python3 as we hope to remove support completely in the next releaase.

1.39.20: 07/20/2020

  • Remove the --save-bc command line option. This was specific to fastcomp, which is deprecated, and for debugging purposes we already have EMCC_DEBUG which saves all intermediate files.
  • It is now an error if a function listed in the EXPORTED_FUNCTIONS list is missing from the build (can be disabled via -Wno-undefined) (ERROR_ON_UNDEFINED_SYMBOLS and WARN_ON_UNDEFINED_SYMBOLS no longer apply to these symbols which are explicly exported).
  • Support for pthreads with wasm2js (WASM=0; #11505).
  • Rename emscripten/math.h to emscripten/em_math.h because if a user adds emscripten/ as an include path with -I, that can override libc math.h, which leads to very confusing errors.

1.39.19: 07/07/2020

  • In standalone mode make main mandatory by default (#11536). To build a library ("reactor"), use --no-entry. The compiler will suggest that if main is not present.
  • Automatically resume AudioContexts on user input in SDL and OpenAL (#10843).
  • Asyncify now does liveness analysis to find which locals to save (Binaryen#2890).
  • Settings on the command line no longer require a space between the -s and the name of the setting. For example, -sEXPORT_ALL is now equivalent to -s EXPORT_ALL.
  • Rename EXCEPTION_CATCHING_WHITELIST to EXCEPTION_CATCHING_ALLOWED. The functionality is unchanged, and the old name will be allowed as an alias for a few releases to give users time to migrate.
  • Add support for the new add-list in Asyncify and update existing list names following the updates in Binaryen, so that now we have ASYNCIFY_ADD to add a function, ASYNCIFY_REMOVE to remove one (previously this was called ASYNCIFY_BLACKLIST), and ASYNCIFY_ONLY to set a list of the only functions to instrument and no others (previously this was called ASYNCIFY_WHITELIST). The updated lists also handle indirect calls properly, so that if you use ASYNCIFY_IGNORE_INDIRECT and then add (using either the add-list or the only-list) all the functions that are on the stack when pausing, then things will work (for more, see WebAssembly/binaryen#2913).

1.39.18: 06/12/2020

  • Disable LIBCXX_ABI_OPTIMIZED_FUNCTION which is an ABI change in libc++ (changing the layout of the std::function object) (#11403).
  • New WASM2C option that integrates with wabt's wasm2c tool in order to compile everything into a single C file (#11213).

1.39.17: 06/05/2020

  • Use Promise polyfill for MODULARIZE when supporting legacy browsers. (#11320)
  • Fix minification of wasm2js output when using --emit-symbol-map. (#11279)
  • On first use, emscripten creates a sample config file. This config file is now created in the emscripten directory by default. The traditional ~/.emscripten config file in the $HOME directory is still supported and the sample config will still be written there in the case that the emscripten root is read-only.
  • The default location for downloaded ports is now a directory called "ports" within the cache directory. In practice these means by default they live in cache/ports inside the emscripten source directory. This can be controlled by setting the location of the cache directory, or for even more fine grained control the EM_PORTS environment variable and the PORTS config setting can be used.
  • Added support for compiling SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE 4.2 and 128-bit wide AVX intrinsics, emulated on top of Wasm SIMD instruction set. (#11193, #11243, #11290, #11327). Pass -msimd128 -msse to enable targeting SSE.
  • Removed obsolete SIMD.js support (-s SIMD=1). Use -msimd128 to target Wasm SIMD. (#11180)
  • Add warning about fastcomp deprecation (can be disabled via -Wno-fastcomp).
  • The mmap method of JavaScript filesystem drivers (based on library_fs.js) no longer takes a target memory. It's safer/cleaner/smaller to assume the target is the global memory buffer.
  • Remove emterpreter and EMTERPRETIFY settings. Emterpreter has largely been replaced by asyncify and is fastcomp only so due for removing in the near future anyway.
  • Upgrade various musl string functions to 1.2 to fix aliasing issues. (#11215)

1.39.16: 05/15/2020

  • Add Math C API for direct access to JavaScript Math object (#11151).

  • Address Sanitizer support now includes JavaScript as well, that is, memory access of HEAP* arrays is checked by ASan. That allows errors to be found if JS glue code does something wrong like forget to shift a pointer. To use this, just build with ASan normally, -fsanitize=address at link (#11147).

  • Fix embind string conversions in multithreaded builds (#10844).

  • ALLOW_MEMORY_GROWTH used to silently disable ABORTING_MALLOC. It now just changes the default, which means you can pass -s ABORTING_MALLOC=1 to override the default, which was not possible before. (If you pass the flag and don't want that behavior, stop passing the flag.) (#11131)

  • Change the factory function created by using the MODULARIZE build option to return a Promise instead of the module instance. That is, beforehand

      Module()
    

    would return an instance (which was perhaps not ready yet if startup was async). In the new model, that returns a Promise which you can do .then or await on to get notified when the instance is ready, and the callback receives the instance. Note that both before and after this change doing Module() creates and runs an instance, so the only change is the return value from that call. This fixes some long-standing bugs with that option which have been reported multiple times, but is a breaking change - sorry about that. To reduce the risk of confusing breakage, in a build with ASSERTIONS we will show a clear warning on common errors. For more, see detailed examples for the current usage in src/settings.js on MODULARIZE. (#10697)

  • A new PRINTF_LONG_DOUBLE option allows printf to print long doubles at full float128 precision. (#11130)

  • emscripten_async_queue_on_thread has been renamed to emscripten_dispatch_to_thread which no longer implies that it is async - the operation is in fact only async if it is sent to another thread, while it is sync if on the same one. A new emscripten_dispatch_to_thread_async function is added which is always async.

  • The emscripten cache now lives in a directory called cache at the root of the emscripten tree by default. The CACHE config setting and the EM_CACHE environment variable can be used to override this (#11126).

  • Honor CACHE setting in config file as an alternative to EM_CACHE environment variable.

  • Remove --cache command line arg. The CACHE config setting and the EM_CACHE environment variable can be used to control this.

  • Compiling to a file with no suffix will now generate an executable (JS) rather than an object file. This means simple cases like emcc -o foo foo.c do the expected thing and generate an executable.

  • System libraries such as libc and libc++ are now included by default at link time rather than selectively included based on the symbols used in the input object files. For small programs that don't use any system libraries this might result in slightly slower link times with the old fastcomp backend. In order to exclude these libraries build with -nostdlib and/or -nostdlib++.

1.39.15: 05/06/2020

  • Add --extern-pre-js and --extern-post-js emcc flags. Files provided there are prepended/appended to the final JavaScript output, after all other work has been done, including optimization, optional MODULARIZE-ation, instrumentation like SAFE_HEAP, etc. They are the same as prepending/ appending those files after emcc finishes running, and are just a convenient way to do that. (For comparison, --pre-js and --post-js optimize that code together with everything else, keep it in the same scope if running MODULARIZE, etc.).
  • Stop defining FE_INEXACT and other floating point exception macros in libc, since we don't support them. That also prevents musl from including code using pragmas that don't make sense for wasm. Ifdef out other uses of those pragmas as well, as tip of tree LLVM now fails to compile them on wasm. (#11087)
  • Update libcxx and libcxxabi to LLVM 10 release branch (#11038).
  • Remove BINARYEN_PASSES setting (#11057). We still have BINARYEN_EXTRA_PASSES (the removed setting completely overrides the set of passes from the command line, which doesn't make much sense as some of them are mandatory like setting the sbrk ptr).
  • Remove MODULARIZE_INSTANCE build option (#11037). This was a seldom used option that was complicating the logic for MODULARIZE. Module instances can be created by using MODULARIZE and calling the factory function explicitly. See the new --extern-post-js option added in this release, which can help code that used MODULARIZE_INSTANCE (you can add an extern post js which does Module = Module(); for example).

1.39.14: 05/01/2020

  • Update SDL2 to latest in ports, which has recently been updated to include upstream 2.0.10.
  • Add warning on use of EMTERPRETIFY which is soon to be removed.
  • Emscripten can now compile assembly files in llvm's .s/.S file format.
  • Remove test-only environment variable handling for EMCC_LEAVE_INPUTS_RAW. The two uses cases in our test code were covered by the -nostdlib option.
  • Remove untested CONFIGURE_CC. This could be used to override the underlying compiler used in emcc/em++ but only during configure tests. There are other ways to control/fake the detected configure features that don't require such monkey patching. For example setting defaults via a site file: https://www.gnu.org/software/autoconf/manual/autoconf-2.67/html_node/Site-Defaults.html
  • Remove undocumented and untested config settings: COMPILER_OPTS. This was a global setting in the emscripten config file that would inject extra compiler options.
  • Allow spaces in a path to Python interpreter when running emscripten from Unix shell (#11005).
  • Support atexit() in standalone mode (#10995). This also fixes stdio stream flushing on exit in that mode.

v1.39.13: 04/17/2020

  • Support for WebAssembly BigInt integration with a new WASM_BIGINT flag. With that the VM will use a JS BigInt for a wasm i64, avoiding the need for JS legalization. See #10860.
  • Add another value for ENVIRONMENT named 'webview' - it is a companion option for 'web' and enables some additional compatibility checks so that generated code works both in normal web and in a webview like Cordova. See #10846

v1.39.12: 04/09/2020

  • Pass linker flags directly to wasm-ld by default. We still filter out certain flags explicitly. If there are other flags that it would be useful for us to ignore we can add them to the list of ignored flags.
  • Optionally support 2GB+ heap sizes. To do this we make the JS code have unsigned pointers (we need all 32 bits in them now), which can slightly increase code size (>>> instead of >>). This only happens when the heap size may be over 2GB, which you must opt into explicitly, by setting MAXIMUM_MEMORY to a higher value (i.e. by default you do not get support for 2GB+ heaps). See #10601
  • --llvm-lto flag is now ignored when using the upstream llvm backend. With the upstream backend LTO is controlled via -flto.
  • Require format string for emscripten_log.
  • Program entry points without extensions are now shell scripts rather than python programs. See #10729. This means that python emcc no longer works. However emcc, emcc.py and python emcc.py all continue to work. The reason for this change is that #!/usr/bin/env python is no longer portable since the python symlink was dropped from Ubuntu 20.04.
  • New EM_IMPORT macro to mark C/C++ symbols as imported from outside the module (i.e. imported from JS). Currently we still default to assuming that all undefined symbols can come from JS, but in the future we hope to mark such symbols explicitly to allow the linker to report on genuinely undefined symbols.
  • Dynamic linking optimizations: Stop emitting unnecessary fp$ and g$ accessors in main modules, possible in Binaryen thanks to ensuring function table indexes are unique (#10741).
  • New JS_MATH option to use Math.* in JS instead of compiled musl (#10821).
  • Pass Module to Module callback functions like Module.preRun (#10777).
  • Support not having ports, for packagers of emscripten that don't want them (#10810).
  • Rename syscalls to have meaningful names (#10750).

v1.39.11: 03/20/2020

  • The default c++ version is no longer fixed at c++03. We now fall back to clang's default which is currently c++14.
  • Remove arc4random function form library.js. This is a BSD-only library function. Anyone requiring BSD compat should be able to use something like https://libbsd.freedesktop.org/.
  • Change the meaning of ASYNCIFY_IMPORTS: it now contains only new imports you add, and does not need to contain the list of default system imports like emscripten_sleep. There is no harm in providing them, though, so this is not a breaking change.
  • Enable DWARF support: When compiling with -g, normal DWARF emitting happens, and when linking with -g we preserve that and update it. This is a change from before, where we assumed DWARF was unneeded and did not emit it, so this can increase the size of debug builds (i.e. builds compiling and/or linking with -g). This change is necessary for full debugging support, that is, to be able to build with -g and use a debugger. Before this change only the -gforce_dwarf flag enabled DWARF; that flag is now removed. If you want the old behavior, build your object files with -gline-tables-only (that will only add line table info, which is just enough for things like source maps and does not include full debug info). For more info and background see #10325.
  • Remove hacks from memset handling, in particular, in the wasm backend, completely remove the JS version of memset from the JS library and from DEFAULT_LIBRARY_FUNCS_TO_INCLUDE. The regular C version will be linked in from compiler_rt normally. A noticeable difference you may see is that a JS library cannot add a __dep to memset - deps only work for JS library functions, but now we only have the regular C version. If you hit that issue, just add _memset to EXPORTED_FUNCTIONS (or adjust deps_info.json).
  • Minimal runtime code size optimizations, see #10725, #10724, #10663.
  • wasm2js fix for a long-existing but very rare correctness bug, see #10682.
  • Use atomics in musl lock/unlock in pthreads builds, which may fix very rare pthreads + stdio issues (none have been reported though). See #10670.

v1.39.10: 03/09/2020

  • Fix a SIMD regression in 1.39.9 (#10658).
  • Fix emscripten_atomic_exchange_u8,16,32,64 (#10657).
  • Switch bzip2 to an emscripten-ports mirror.

v1.39.9: 03/05/2020

  • Add support for -Wall, -Werror, -w, -Wno-error=, -Werror=, for controlling internal emscripten errors. The behavior of these flags matches the gcc/clang counterparts.
  • Rename TOTAL_MEMORY to INITIAL_MEMORY and WASM_MEM_MAX to MAXIMUM_MEMORY, which are more accurate and match wasm conventions. The old names are still supported as aliases.
  • Updated of libc++abi and libc++ to llvm 9.0.0 (#10510)
  • Refactor syscall interface: Syscalls are no longer variadic (except those that are inherently such as open) and no longer take the syscall number as arg0. This should be invisible to most users but will effect any external projects that try to implement/emulate the emscripten syscall interface. See #10474
  • Removed src/library_vr.js, as it was outdated and nonfunctional, and the WebVR specification has been obsoleted in favor of the upcoming WebXR specification. (#10460)
  • Deprecate WASM_OBJECT_FILES setting. There are many standard ways to enable bitcode objects (-flto, -flto=full, -flto=thin, -emit-llvm).
  • Removed EmscriptenWebGLContextAttributes::preferLowPowerToHighPerformance option that has become unsupported by WebGL. Access EmscriptenWebGLContextAttributes::powerPreference instead. (#10505)
  • When implementing forwarding function aliases in JS libraries, either the alias or the target function must contain a signature annotation. (#10550)
  • Add a check in Asyncify builds with ASSERTIONS that we do not have compiled code on the stack when starting to rewind, which is dangerous.
  • Implement libc system() for node.js (#10547).
  • Standalone mode improvements, time (#10530, #10536), sysconf (#10535), getpagesize (#10533), _Exit (#10534)
  • Fix many closure compiler warnings (e.g. #10525).
  • Avoid unnecessary syscall proxying (#10511).
  • Added new link time command line option -jsDfoo=val to allow specifying custom preprocessor options to JS library files. (#10624, #10580)

v1.39.8: 02/14/2020

  • Add LLD_REPORT_UNDEFINED option that should allow for more detailed diagnostics when symbols are undefined at link time. This currently has some limitations and is not enabled by default. For example, EM_JS symbols are reported as undefined at link time, as are __invoke_* functions.
  • wasm2js optimizations. See binaryen#2623.
  • WebGPU Compute fixes. Simple examples now work. See #10367.
  • Many DWARF debug info fixes. Emitting of DWARF is correct as far as we know, including when optimizing (a few passes are disabled for now, but almost all work). We still only generate it behind the -gforce_dwarf flag for now, though (but that should be removed soon).

v1.39.7: 02/03/2020

  • The checked-in copy of the Closure compiler was removed in favor of getting it from npm. This means that developers now need to run npm install after checking out emscripten if they want to use closure (--closure). emsdk users are not effected because emsdk runs this as a post install step (#9989).
  • Added support for specifying JSDoc minification annotations for Closure in JS library, pre and post files. See https://github.com/google/closure-compiler/wiki/Annotating-JavaScript-for-the-Closure-Compiler (#10272)
  • Add new Fibers API for context switching, that supersedes the old coroutine API that only ran on fastcomp. See #9859
  • Added new linker option -s WASM=2 which produces a dual Wasm+JS build, which falls back to using a JavaScript version if WebAssembly is not supported in target browser/shell. (#10118)
  • Added new linker option -s CLOSURE_WARNINGS=quiet|warn|error that allows aborting the build if the Closure compiler produced any warnings.

v1.39.6: 01/15/2020

  • Development has switched from the "incoming" branch to "master".
  • Added new system header <emscripten/heap.h>, which enables querying information about the current WebAssembly heap state.
  • Reduced default geometric memory overgrowth rate from a very generous 2x factor to a more memory conserving +20% factor, and capped maximum reservation to 96MB at most.
  • Added options MEMORY_GROWTH_GEOMETRIC_STEP and MEMORY_GROWTH_GEOMETRIC_CAP to allow customizing the heap growth rates.
  • Renamed MEMORY_GROWTH_STEP option to MEMORY_GROWTH_LINEAR_STEP option.
  • Added new linker option -s HTML5_SUPPORT_DEFERRING_USER_SENSITIVE_REQUESTS=0 (default enabled) to allow disabling support for deferred fullscreen mode and pointer lock requests for applications that do not need deferring support.

v1.39.5: 12/20/2019

  • Added support for streaming Wasm compilation in MINIMAL_RUNTIME (off by default)
  • All ports now install their headers into a shared directory under EM_CACHE. This should not really be a user visible change although one side effect is that once a given port is built, its headers are then universally accessible, just like the library is universally available as -l<name>.
  • Removed timestamp field from mouse, wheel, devicemotion and deviceorientation events. The presence of a timestamp on these events was slightly arbitrary, and populating this field caused a small profileable overhead that all users might not care about. It is easy to get a timestamp of an event by calling emscripten_get_now() or emscripten_performance_now() inside the event handler function of any event.
  • Add fine-grained options for specific legacy browser support, MIN_FIREFOX_VERSION, MIN_SAFARI_VERSION, MIN_IE_VERSION, MIN_EDGE_VERSION, MIN_CHROME_VERSION. The existing LEGACY_VM_SUPPORT option sets all of them to 0, that is, maximal backwards compatibility. Note that going forward, we will use these settings in more places, so if you do need very old legacy browser support, you may need to set either LEGACY_VM_SUPPORT or the fine-grained options. For more details see #9937
  • Default DISABLE_DEPRECATED_FIND_EVENT_TARGET_BEHAVIOR to 1. See #9895. With this change the old deprecated HTML5 API event target lookup behavior is disabled. There is no "Module.canvas" object, no magic "null" default handling, and DOM element 'target' parameters are taken to refer to CSS selectors, instead of referring to DOM IDs. For more information see: https://groups.google.com/forum/#!msg/emscripten-discuss/xScZ_LRIByk/_gEy67utDgAJ
  • WASI API updated from wasi_unstable to wasi_snapshot_preview1. This is mostly an implementation detail, but if you use STANDALONE_WASM it means that the output of emscripten now requires a runtime with wasi_snapshot_preview1 support.
  • SAFE_STACK has been removed, as it overlaps with STACK_OVERFLOW_CHECK. Replace SAFE_STACK=1 with STACK_OVERFLOW_CHECK=2 (note the value is 2). This also has the effect of enabling stack checking on upstream builds when ASSERTIONS are enabled (as assertions enable STACK_OVERFLOW_CHECK=2).

v1.39.4: 12/03/2019

  • Remove deprecated requestFullScreen method from library_browser.js, please use requestFullscreen (without the capital S).
  • Remove deprecated requestFullScreen and cancelFullScreen from library_glut.js
  • Remove deprecated requestFullScreen and cancelFullScreenfrom library_glfw.js
  • Fix SDL2_mixer support for ogg vorbis. See #9849
  • Various source maps fixes, see #9926 #9882 #9837 #9814

v1.39.3: 11/14/2019

v1.39.2: 11/06/2019

  • Archives with missing indexes will now have ranlib run on them automatically at link time. This avoids linker errors when using GNU ar to build archive files.
  • ERROR_ON_MISSING_LIBRARIES now also applies to internal symbols that start with emscripten_. Prior to this change such missing symbols would result in a runtime error, now they are reported at compile time.
  • Pthread blocking on the main thread will now warn in the console. If ALLOW_BLOCKING_ON_MAIN_THREAD is unset then the warning is an error.
  • Add pthread_tryjoin_np, which is a POSIX API similar to pthread_join but without blocking.
  • New function emscripten_has_asyncify().
  • Add support for pthreads in Node.js, using Node Workers. See #9745

v1.39.1: 10/30/2019

  • Only MEMFS is included by default, others (NODEFS, IDBFS, WORKERFS, PROXYFS) must be linked in explicitly, using -lnodefs.js, -lidbfs.js', -lworkerfs.js, -lproxyfs.js. See #9645

v1.39.0: 10/18/2019

  • The emsdk defaults to the upstream backend (instead of fastcomp) from this release onward (but both backends are still fully supported). See https://emscripten.org/docs/compiling/WebAssembly.html#backends
  • Add support for overriding .emscripten config variables using environment variables. Any config variable FOO can be overridden by EM_FOO in the environment.
  • -Werror now also turns warnings in the python driver code into errors.
  • Internal settings have moved from settings.js to settings_internal.js. These are settings that are for internal use only and are not set-able from the command line. If we misclassified any of these please open a bug.
  • STANDALONE_WASM mode now supports setting up argv via wasi APIs.
  • STANDALONE_WASM mode now supports running static constructors in _start.

v1.38.48: 10/11/2019

  • Add support for MAIN_THREAD_EM_ASM in wasm backend. #9560
  • Add ability to disable FETCH worker in Fastcomp backend via USE_FETCH_WORKER=0. This is useful for people who use FETCH, but don't perform any synchronous fetches on the main thread. #9567
  • Remove EMCONFIGURE_JS. Since #6269 we have set it to "2" which means never use native, always use JS.

v1.38.47: 10/02/2019

  • Add support for FETCH API in WASM backend. This doesn't support FETCH in the main thread (USE_FETCH_WORKER=0 is enforced). #9490
  • Redefine errno values to be consistent with wasi. This will let us avoid needing to convert the values back and forth as we use more wasi APIs. This is an ABI change, which should not be noticeable from user code unless you use errno defines (like EAGAIN) and keep around binaries compiled with an older version that you link against. In that case, you should rebuild them. See #9545.
  • Removed build option -s ONLY_MY_CODE as we now have much better solutions for that, like building to a wasm object file or using STANDALONE_WASM etc. (see https://github.com/emscripten-core/emscripten/wiki/WebAssembly-Standalone).
  • Emscripten now supports the config file (.emscripten) being placed in the emscripten directory rather that the current user's home directory. See #9543

v1.38.46: 09/25/2019

  • Rename libpthreads to libpthread to match its normal name on other platforms. This change should be completely internal to emscripten.
  • Remove redundant COMPILER_ENGINE and JS_ENGINE options. We only support node as the compiler engine so just use a single NODE_JS option for that.
  • Module.abort is no longer exported by default. It can be exported in the normal way using EXTRA_EXPORTED_RUNTIME_METHODS, and as with other such changes in the past, forgetting to export it will show a clear error in ASSERTIONS mode.
  • Remove EMITTING_JS flag, and replace it with STANDALONE_WASM. That flag indicates that we want the wasm to be as standalone as possible. We may still emit JS in that case, but the JS would just be a convenient way to run the wasm on the Web or in Node.js.
  • ASYNCIFY_BLACKLIST and ASYNCIFY_WHITELIST now support simple '*' wildcard matching

v1.38.45: 09/12/2019

v1.38.44: 09/11/2019

  • Remove Binaryen from the ports system. This means that emscripten will no longer automatically build Binaryen from source. Instead, either use the emsdk (binaries are provided automatically, just like for LLVM), or build it yourself and point BINARYEN_ROOT in .emscripten to it. See #9409

v1.38.43: 08/30/2019

  • noExitRuntime is no longer a property on the Module object. Use noExitRuntime instead of Module.noExitRuntime.

v1.38.42: 08/19/2019

  • Add support for address sanitizer and standalone leak sanitizer with multiple threads. (#9060, #9076)
  • Remove ERROR_ON_MISSING_LIBRARIES setting (it's always on now)
  • Remove the ability to use Python operators in flags that support KB/MB/GB/TB suffixes, e.g. TOTAL_MEMORY. This means that -s TOTAL_MEMORY=1024*1024 will no longer work. This is done because the mechanism may result in execution of arbitrary code via command line flags.

v1.38.41: 08/07/2019

  • Remove fastcomp's implementation of Asyncify. This has been deprecated for a long time, since we added Emterpreter-Async, and now we have a new Asyncify implementation in the upstream wasm backend. It is recommended to upgrade to the upstream backend and use Asyncify there if you need it. (If you do still need the older version, you can use 1.38.40.)
  • Drop ExitStatus from inheriting from Error(), as that could capture the whole global scope, preventing temporary variables at page startup from being garbage collected. (#9108)
  • __builtin_return_address now requires -s USE_OFFSET_CONVERTER=1 to work. (#9073)
  • emrun now uses HTTP/1.1 instead of HTTP/1.0.
  • callMain is no longer exported by default on Module, to allow better JS minification. You must add it to EXTRA_EXPORTED_RUNTIME_METHODS if you want to call it on Module. (In assertions builds, an error with an explanation is shown.)
  • Allow expressions with side effects as EM_ASM's arguments and prohibit non-arithmetic arguments (e.g. pointers, functions, arrays, objects). (#9054)
  • emcc on Windows now uses native newline byte sequence to get a line to print for parse error reporting. (#9088)
  • Internal API update: one can now specialize embind's (un)marshalling for a group of types via SFINAE, instead of a single type. (#9089)
  • Options passed on the Module object during startup, like Module.arguments, are now copied to a local (in order to avoid writing Module.* everywhere, which wastes space). You can still provide them as always, but you can't modify Module.arguments and other things after startup (which is now after we've finished processing them). In a build with assertions enabled you will get an error if you access those properties after startup. (#9072)

v1.38.40: 07/24/2019

  • LLVM backend pthread builds no longer use external memory initialization files, replacing them with passive data segments.
  • LLVM backend now supports thread local storage via the C extension __thread and the C11/C++11 keyword thread_local. (#8976)
  • Internal API change: Move read, readAsync, readBinary, setWindowTitle from the Module object to normal JS variables. If you use those internal APIs, you must change Module.readAsync()/Module['readAsync']() to readAsync(). Note that read is also renamed to read_ (since "read" is an API call in the SpiderMonkey shell). In builds with ASSERTIONS, an error message is shown about the API change. This change allows better JS minification (the names read, readAsync etc. can be minified, and if the variables are not used they can be removed entirely). Defining these APIs on Module (which was never documented or intended, but happened to work) is also no longer allowed (but you can override read_ etc. from JS).

v1.38.39: 07/16/2019

  • Add support for address sanitizer. (#8884)
    • Currently, only supports one thread without dynamic linking.
  • Rename Bysyncify (the name used during development) to Asyncify. This keeps the name consistent with the old ASYNCIFY flag, no need for a new one, as they basically do the same thing.

v1.38.38: 07/08/2019

v1.38.37: 06/26/2019

  • Set ENV['LANG'] following the user's preferred language (HTTP Accept-Language / navigator.languages[0])
  • emscripten_run_script_string now returns C NULL instead of the string null or undefined when the result of the eval is JavaScript null or undefined.
  • Add a new system for managing system libraries. (#8780) This may require minor changes when performing certain operations:
    • When using embuilder.py to build a specific library, the name may have changed: for consistency, all library names are prefixed with lib now.
    • embuilder.py now only builds the requested library, and not its dependencies and certain system libraries that are always built. For example, running embuilder.py build libc no longer builds libcompiler_rt if it hasn't be built.
    • When using EMCC_FORCE_STDLIBS with a list of libraries, you must now use the simplified names, for example, libmalloc and libpthreads instead of libdlmalloc or libpthreads_stub. These names will link in the correct version of the library: if the build is configured to use emmalloc, libmalloc will mean libemmalloc, and if thread support is disabled, libpthreads will mean libpthreads_stub. This allows you to say libmalloc or libpthreads without worrying about which implementation is supposed to be used, and avoid duplicate symbols if you used the wrong implementation.
  • LLVM wasm backend pthreads fixes, see #8811, #8718

v1.38.36: 06/15/2019

v1.38.35: 06/13/2019

  • Include some waterfall fixes for the emsdk builds on linux regarding libtinfo.
  • NOTE: due to a CI failure, builds for mac and windows were not generated.

v1.38.34: 06/01/2019

  • Add support for undefined behavior sanitizer.
    • This allows emcc -fsanitize=undefined to work. (#8651)
    • The minimal runtime (-fsanitize-minimal-runtime) also works. (#8617)

v1.38.33: 05/23/2019

v1.38.32: SKIPPED

  • The transition from the old to the new CI occurred around here. To avoid ambiguity while both CIs were still generating builds, we just tagged a new one (1.38.33) on the new CI and skipped 1.38.32.
  • The transition also moves all builds and downloads away from the old mozilla-games infrastructure to the new chromium ones. As a result all links to mozilla-games URLs will not work (these were never documented, but could be seen from the internals of the emsdk; the new emsdk uses the proper new URLs, so you can either use the sdk normally or find the URLs from there).

v1.38.31: 04/24/2019

  • Change ino_t/off_t to 64-bits. (#8467)
  • Add port for bzip2 library (libbz2.a). (#8349)
  • Add port for libjpeg library. (#8361)
  • Enable ERROR_ON_MISSING_LIBRARIES by default (#8461)

v1.38.30: 03/21/2019

  • Remove Module.buffer which was exported by default unnecessarily. This was an undocumented internal detail, but in theory, code may have relied on it. (#8277)

v1.38.29: 03/11/2019

v1.38.28: 02/22/2019

  • Option -s EMTERPRETIFY_WHITELIST now accepts shell-style wildcards; this allows matching static functions with conflicting names that the linker distinguishes by appending a random suffix.
  • Normalize mouse wheel delta in library_browser.js. This changes the scroll amount in SDL, GLFW, and GLUT. (#7968)

v1.38.27: 02/10/2019

  • Change how EMCC_LOCAL_PORTS works, to be more usable. See #7963
  • Remove deprecated Pointer_stringify (use UTF8ToString instead). See #8011
  • Added a new option -s DISABLE_DEPRECATED_FIND_EVENT_TARGET_BEHAVIOR=1 that changes the lookup semantics of DOM elements in html5.h event handler callbacks and WebGL context creation. The new behavior is to use CSS selector strings to look up DOM elements over the old behavior, which was somewhat ad hoc constructed rules around default Emscripten uses. The old behavior will be deprecated and removed in the future. Build with -s ASSERTIONS=1 to get diagnostics messages related to this transition.
  • Breaking change with -s USE_PTHREADS=1 + -s FETCH=1: When building with -o a.html, the generated worker script is now named "a.fetch.js" according to the base name of the specified output, instead of having a fixed name "fetch-worker.js".

v1.38.26: 02/04/2019

  • Fix some pthreads proxying deadlocks. See #7865

v1.38.25: 01/18/2019

  • Move kripken/emscripten,emscripten-fastcomp,emscripten-fastcomp-clang to emscripten-core/*

v1.38.24: 01/17/2019

  • Perform JS static allocations at compile time (#7850)

v1.38.23: 01/10/2019

  • Remove BINARYEN_METHOD: no more support for interpret modes, and if you want non-wasm, use WASM=0.
  • Support specifying multiple possible ENVIRONMENTs (#7809)

v1.38.22: 01/08/2019

  • Add Regal port. See #7674
  • System libraries have been renamed to include the lib prefix. If you use EMCC_FORCE_STDLIBS or EMCC_ONLY_FORCED_STDLIBS to select system libraries you may need to add the lib prefix.
  • Rename pthread-main.js to NAME.worker.js, where NAME is the main name of your application, that is, if you emit program.js then you'll get program.worker.js (this allows more than one to exist in the same directory, etc.).
  • Dynamic linker has been taught to handle library -> library dependencies.

v1.38.21: 11/30/2018

  • fastcomp: Remove runPostSets function and replace with normal static constructor function. See #7579

v1.38.20: 11/20/2018

  • Remove SPLIT_MEMORY option.
  • Move getTempRet0/setTempRet0 to be JS library functions rather than auto-generated by fastcomp.
  • Change strptime()'s handling of the "%c" to match that of strftime(). This is a breaking change for code which depends on the old definition of "%c".

v1.38.19: 11/15/2018

v1.38.18: 11/08/2018

  • Wasm dynamic linking: Rename tableBase/memoryBase to __table_base/__memory_base (#7467)

v1.38.17: 11/07/2018

  • Minify wasm import and export names. This decreases JS and wasm size by minifying the identifiers where JS calls into wasm or vice versa, which are not minifiable by closure or other JS-only tools. This happens in -O3, -Os and above. See #7431

v1.38.16: 11/02/2018

  • Breaking change: Do not automatically set EXPORT_ALL for MAIN_MODULES or SIDE_MODULES. This means that you must explicitly export things that will be called from outside (normally, on EXPORTED_FUNCTIONS), or you can manually enable EXPORT_ALL yourself (which returns to the exact same behavior as before). This change brings us in line with more standard dynamic linking, and will match what the LLVM wasm backend will have. See #7312.
  • Invalid -s flags on the command line are now treated as errors.
  • Remove BUILD_AS_SHARED_LIBRARY setting.

v1.38.15: 10/25/2018

v1.38.14: 10/22/2018

  • Errors are now reported when functions listed in EXPORTED_FUNCTIONS are not defined. This can be disabled via ERROR_ON_UNDEFINED_SYMBOLS=0. See #7311.

v1.38.13: 10/10/2018

  • Support -s NO_X=1 as an alias for -s X=0 and vice versa, which simplifies current settings with NO_-prefixed names. See #7151.
  • Various EMULATED_FUNCTION_POINTER improvements. See #7108, #7128.
  • ERROR_ON_UNDEFINED_SYMBOLS is now the default. See #7196

v1.38.12: 09/03/2018

  • Update SDL2 to 2.0.7. See #7016.
  • Optionally build using native object files (wasm backend only). For now this is behind a new option flag: -s WASM_OBJECT_FILES=1. See #6875.

v1.38.11: 08/02/2018

  • Support for loading wasm files in the same dir as the JS file, using node.js/Web-specific techniques as applicable. See #5368 and followups.
  • Add an API for async side module compilation in wasm. See #6663.
  • Remove builtin Crunch support. See #6827.

v1.38.10: 07/23/2018

  • Change the type of size_t and friends from int to long. This may have noticeable effects if you depend on the name mangling of a function that uses size_t (like in EXPORTED_FUNCTIONS), and you must rebuild source files to bitcode (so your bitcode is in sync with the system libraries after they are rebuilt with this change). Otherwise this should not have any noticeable effects for users. See #5916.

v1.38.9: 07/22/2018

  • Fix Module.locateFile to resolve relative paths to *.wasm, *.mem and other files relatively to the main JavaScript file rather than the current working directory (see #5368).
    • Add second argument prefix to Module.locateFile function that contains the path to the JavaScript file where files are loaded from by default.
    • Remove Module.*PrefixURL APIs (use Module.locateFile instead).

v1.38.8: 07/06/2018

  • Fix a regression in 1.38.7 with binaryen no longer bundling binaryen.js (which emscripten doesn't need, that's just for handwritten JS users, but emscripten did check for its presence).

v1.38.7: 07/06/2018

  • Correctness fix for stack handling in invoke_*()s. This may add noticeable overhead to programs using C++ exceptions and (less likely) setjmp/longjmp - please report any issues. See #6666 #6702
  • Deprecate Module.ENVIRONMENT: Now that we have a compile-time option to set the environment, also having a runtime one on Module is complexity that we are better off without. When Module.ENVIRONMENT is used with ASSERTIONS it will show an error to direct users to the new option (-s ENVIRONMENT=web , or node, etc., at compile time).
  • Breaking change: Do not export print/printErr by default. Similar to other similar changes (like getValue/setValue). We now use out() and err() functions in JS to print to stdout/stderr respectively. See #6756.

v1.38.6: 06/13/2018

v1.38.5: 06/04/2018

  • Update libc++ to 6.0, bringing c++17 support (std::byte etc.)

v1.38.4: 05/29/2018

  • Fix asm.js validation regression from 1.38.2.

v1.38.3: 05/25/2018

  • Upgrade to LLVM 6.0.1.

v1.38.2: 05/25/2018

  • Add ENVIRONMENT option to specify at compile time we only need JS to support one runtime environment (e.g., just the web). When emitting HTML, set that to web so we emit web code only. #6565
  • Regression in asm.js validation due to cttz optimization #6547

v1.38.1: 05/17/2018

  • Remove special-case support for src/struct_info.compiled.json: Make it a normal cached thing like system libraries, not something checked into the source tree.
  • Breaking change: Emit WebAssembly by default. Only the default is changed - we of course still support asm.js, and will for a very long time. But changing the default makes sense as the recommended output for most use cases should be WebAssembly, given it has shipped in all major browsers and platforms and is more efficient than asm.js. Build with -s WASM=0 to disable wasm and use asm.js if you want that (or use -s LEGACY_VM_SUPPORT=1, which emits output that can run in older browsers, which includes a bunch of polyfills as well as disables wasm). (#6419)

v1.38.0: 05/09/2018

v1.37.40: 05/07/2018

  • Fix regression in 1.37.39 on -s X=@file parsing (see #6497, #6436)

v1.37.39: 05/01/2018

  • Regression: Parsing of -s X=@file broke if the file contains a newline (see #6436; fixed in 1.37.40)

v1.37.38: 04/23/2018

  • Breaking change: Simplify exception handling, disabling it by default. Previously it was disabled by default in -O1 and above and enabled in -O0, which could be confusing. You may notice this change if you need exceptions and only run in -O0 (since if you test in -O1 or above, you'd see you need to enable exceptions manually), in which case you will receive an error at runtime saying that exceptions are disabled by default and that you should build with -s DISABLE_EXCEPTION_CATCHING=0 to enable them.
  • Fix regression in 1.37.37 on configure scripts on MacOS (see #6456)

v1.37.37: 04/13/2018

  • Regression: configure scripts on MacOS may be broken (see #6456; fixed in 1.37.38)

v1.37.36: 03/13/2018

v1.37.35: 02/23/2018

  • MALLOC option, allowing picking between dlmalloc (previous allocator and still the default) and emmalloc, a new allocator which is smaller and simpler.
  • Binaryen update that should fix all known determinism bugs.

v1.37.34: 02/16/2018

  • addFunction is now supported on LLVM wasm backend, but when being used on the wasm backend, you need to provide an additional second argument, a Wasm function signature string. Each character within a signature string represents a type. The first character represents the return type of a function, and remaining characters are for parameter types.
    • 'v': void type
    • 'i': 32-bit integer type
    • 'j': 64-bit integer type (currently does not exist in JavaScript)
    • 'f': 32-bit float type
    • 'd': 64-bit float type For asm.js and asm2wasm you can provide the optional second argument, but it isn't needed. For that reason this isn't a breaking change, however, providing the second argument is recommended so that code is portable across all backends and modes.

v1.37.33: 02/02/2018

v1.37.32: 01/31/2018

v1.37.31: 01/31/2018

  • LLVM and clang updates from upstream (5.0svn, close 5.0 release).

v1.37.30: 01/31/2018

v1.37.29: 01/24/2018

v1.37.28: 01/08/2018

  • Breaking change: Don't export the ALLOC_* numeric constants by default. As with previous changes, a warning will be shown in -O0 and when ASSERTIONS are on if they are used.
  • Breaking change: Don't export FS methods by default. As with previous changes, a warning will be shown in -O0 and when ASSERTIONS are on, which will suggest either exporting the specific methods you need, or using FORCE_FILESYSTEM which will auto export all the main filesystem methods. Aside from using FS methods yourself, you may notice this change when using a file package created standalone, that is, by running the file packager directly and then loading it at run time (as opposed to telling emcc to package the files for you, in which case it would be aware of them at compile time); you should build with FORCE_FILESYSTEM to ensure filesystem support for that case.

v1.37.27: 12/24/2017

  • Breaking change: Remove the Runtime object, and move all the useful methods from it to simple top-level functions. Any usage of Runtime.func should be changed to func.

v1.37.26: 12/20/2017

  • Breaking change: Change NO_EXIT_RUNTIME to 1 by default. This means that by default we don't include code to shut down the runtime, flush stdio streams, run atexits, etc., which is better for code size. When ASSERTIONS is on, we warn at runtime if there is text buffered in the streams that should be flushed, or atexits are used.
  • Meta-DCE for JS+wasm: remove unused code between JS+wasm more aggressively. This should not break valid code, but may break code that depended on unused code being kept around (like using a function from outside the emitted JS without exporting it - only exported things are guaranteed to be kept alive through optimization).

v1.37.24: 12/13/2017

  • Breaking change: Similar to the getValue/setValue change from before (and with the same ASSERTIONS warnings to help users), do not export the following runtime methods by default: ccall, cwrap, allocate, Pointer_stringify, AsciiToString, stringToAscii, UTF8ArrayToString, UTF8ToString, stringToUTF8Array, stringToUTF8, lengthBytesUTF8, stackTrace, addOnPreRun, addOnInit, addOnPreMain, addOnExit, addOnPostRun, intArrayFromString, intArrayToString, writeStringToMemory, writeArrayToMemory, writeAsciiToMemory.

v1.37.23: 12/4/2017

  • Breaking change: Do not polyfill Math.{clz32, fround, imul, trunc} by default. A new LEGACY_VM_SUPPORT option enables support for legacy browsers. In ASSERTIONS mode, a warning is shown if a polyfill was needed, suggesting using that option.
  • Breaking change: Do not export getValue/setValue runtime methods by default. You can still use them by calling them directly in code optimized with the main file (pre-js, post-js, js libraries; if the optimizer sees they are used, it preserves them), but if you try to use them on Module then you must export them by adding them to EXTRA_EXPORTED_RUNTIME_METHODS. In -O0 or when ASSERTIONS is on, a run-time error message explains that, if they are attempted to be used incorrectly.

v1.37.17: 7/25/2017

  • Updated to libc++'s "v2" ABI, which provides better alignment for string data and other improvements. This is an ABI-incompatible change, so bitcode files from previous versions will not be compatible.

v1.37.13: 5/26/2017

  • Improved Android support for emrun.
  • Duplicate function elimination fixes (#5186)
  • Fix problem with embinding derived classes (#5193)
  • Fix CMake compiler detection when EMCC_SKIP_SANITY_CHECK=1 is used. (#5145)
  • Implemented GLFW Joystick API (#5175)
  • Fixed a bug with emcc --clear-ports command (#5248)
  • Updated Binaryen to version 33.
  • Full list of changes:

v1.37.12: 5/1/2017

v1.37.11: 5/1/2017

v1.37.10: 4/20/2017

v1.37.9: 3/23/2017

v1.37.8: 3/17/2017

v1.37.7: 3/15/2017

v1.37.6: 3/15/2017

v1.37.5: 3/13/2017

v1.37.4: 3/13/2017

  • Fixed glGetUniformLocation() to work according to spec with named uniform blocks.
  • Fixed WebAssembly Memory.grow() to work.
  • Switched to 16KB page size from earlier 64KB.
  • Optimize alBufferData() operation.
  • Fixed a resource lookup issue with multiple OpenAL audio contexts.
  • Full list of changes:

v1.37.3: 2/16/2017

v1.37.2: 1/31/2017

  • Fixed a build error with boolean SIMD types.
  • Improved WebAssembly support, update Binaryen to version 22.
  • Update GL, GLES, GLES2 and GLES3 headers to latest upstream Khronos versions.
  • Implement support for new garbage free WebGL 2 API entrypoints which improve performance and reduce animation related stuttering.
  • Fixed a bug where -s USE_PTHREADS builds would not have correct heap size if -s TOTAL_MEMORY is not being used.
  • Fixed array type issue that prevented glTexImage3D() and glTexSubImage3D() from working.
  • Full list of changes:

v1.37.1: 12/26/2016

v1.37.0: 12/23/2016

v1.36.14: 11/3/2016

  • Added support to emscripten_async_wget() for relative paths.
  • Fixed FS.mkdirTree('/') to work.
  • Updated SDL 2 port to version 12.
  • Added more missing pthreads stubs.
  • Normalize system header includes to use the preferred form #include <emscripten/foo.h> to avoid polluting header include namespaces.
  • Fixed a bug where transitioning to fullscreen could cause a stack overflow in GLFW.
  • Added new system CMake option -DEMSCRIPTEN_GENERATE_BITCODE_STATIC_LIBRARIES=ON to choose if static libraries should be LLVM bitcode instead of .a files.
  • Improved SIMD support to be more correct to the spec.
  • Updated Binaryen to version 18. (#4674)
  • Fixed dlopen with RTLD_GLOBAL parameter.
  • Full list of changes:

v1.36.13: 10/21/2016

v1.36.12: 10/20/2016

  • Improved Emscripten toolchain profiler with more data. (#4566)
  • Export dlmalloc() and dlfree() as emscripten_builtin_malloc() and emscripten_builtin_free() to allow user applications to hook into memory allocation (#4603)
  • Improved asm.js -s USE_PTHREADS=2 build mode compatibility when multithreading is not supported.
  • Improved WebGL support with closure compiler (#4619)
  • Improved Bianaryen WebAssembly support
  • Added support for GL_disjoint_timer_query extension (#4575)
  • Improved Emscripten compiler detection with CMake (#4129, #4314, #4318)
  • Added support for int64 in wasm.
  • Optimize small constant length memcpys in wasm.
  • Full list of changes:

v1.36.11: 9/24/2016

v1.36.10: 9/24/2016

  • Improved compiler logging print messages on first run experience. (#4501)
  • Fixed log printing in glFlushMappedBufferRange() and glGetInfoLog() functions. (#4521)
  • Added setjmp/longjmp handling for wasm.
  • Improved support for --proxy-to-worker build mode.
  • Improved GLES3 support for glGet() features that WebGL2 does not have. (#4514)
  • Added support for implementation defined glReadPixels() format.
  • Improved WebGL 2 support with closure compilter. (#4554)
  • Implemented support for nanosleep() when building in pthreads mode (#4578)
  • Added support for llvm_ceil_f64 and llvm_floor_f64 intrinsics.
  • Full list of changes:

v1.36.9: 8/24/2016

v1.36.8: 8/20/2016

  • Fixed a memory leak in ctor_evaller.py on Windows (#4446)
  • Migrate to requiring CMake 3.4.3 as the minimum version for Emscripten CMake build integration support.
  • Fixed an issue that prevented -s INLINING_LIMIT from working (#4471)
  • Fixed a bug with Building.llvm_nm interpretation of defined symbols (#4488)
  • Add support for DISABLE_EXCEPTION_CATCHING and EXCEPTION_CATCHING_WHITELIST options for wasm.
  • Added new emprofile.py script which can be used to profile toolchain wide performance. (#4491)
  • Added new linker flag --output-eol, which specifices what kind of line endings to generate to the output files. (#4492)
  • Fixed a Windows bug where aborting execution with Ctrl-C might hang Emscripten to an infinite loop instead. (#4494)
  • Implement support for touch events to GLUT (#4493)
  • Deprecated unsafe function writeStringToMemory() from src/preamble.js. Using stringToUTF8() is recommended instead. (#4497)
  • Full list of changes:

v1.36.7: 8/8/2016

v1.36.6: 8/8/2016

  • Fixed wheelDelta for MSIE (#4316)
  • Fixed inconsistencies in fullscreen API signatures (#4310, #4318, #4379)
  • Changed the behavior of Emscripten WebGL createContext() to not forcibly set CSS style on created canvases, but let page customize the style themselves (#3406, #4194 and #4350, #4355)
  • Adjusted the reported GL_VERSION field to adapt to the OpenGL ES specifications (#4345)
  • Added support for GLES3 GL_MAJOR/MINOR_VERSION fields. (#4368)
  • Improved -s USE_PTHREADS=1 and --proxy-to-worker linker options to be mutually compatible. (#4372)
  • Improved IDBFS to not fail on Safari where IndexedDB support is spotty (#4371)
  • Improved SIMD.js support when using Closure minifier. (#4374)
  • Improved glGetString to be able to read fields from WEBGL_debug_renderer_info extension. (#4381)
  • Fixed an issue with glFramebufferTextureLayer() not working correctly.
  • Fixed a bug with std::uncaught_exception() support (#4392)
  • Implemented a multiprocess lock to access the Emscripten cache. (#3850)
  • Implemented support for the pointerlockerror event in HTML5 API (#4373)
  • Report WebGL GLSL version number in GL_SHADING_LANGUAGE_VERSION string (#4365)
  • Optimized llvm_ctpop_i32() and conversion of strings from C to JS side (#4402, #4403)
  • Added support for the OffscreenCanvas proposal, and transferring canvases to offscreen in pthreads build mode, linker flag -s OFFSCREENCANVAS_SUPPORT=0/1 (#4412)
  • Fixed an issue after updating to new LLVM version that response files passed to llvm-link must have forward slashes (#4434)
  • Fixed a memory leak in relooper in LLVM.
  • Full list of changes:

v1.36.5: 5/24/2016

  • Added support for passing custom messages when running in web worker.
  • Improved fp128 support when targeting WebAssembly.
  • Updated cpuprofiler.js to support tracing time spent in WebGL functions.
  • Fixed an issue with glFenceSync() function call signature (#4260, #4339)
  • Added missing zero argument version of emscripten_sync_run_in_main_thread().
  • Improves support for targeting pthreads when using Closure minifier (#4348).
  • Fixed an issue where pthreads enabled code did not correctly validate as asm.js
  • Fixed an issue with incorrect SIMD.js related imports (#4341)
  • Full list of changes:

v1.36.4: 5/9/2016

  • Added EM_TRUE and EM_FALSE #defines to html5.h.
  • Fixed an issue with GLFW window and framebuffer size callbacks.
  • Added support for more missing WebGL 2 texture formats (#4277)
  • Added support for source files with no extension.
  • Updated emrun.py to latest version, adds support to precompressed content and running as just a web server without launching a browser.
  • Updated experimental WebAssembly support to generate 0xb version code.
  • Automatically build Binaryen when needed.
  • Updated libc++ to SVN revision 268153. (#4288)
  • Full list of changes:

v1.36.3: 4/27/2016

v1.36.2: 4/22/2016

  • Improve support for targeting WebAssembly with Binaryen.
  • Improve support for LLVM's WebAssembly backend (EMCC_WASM_BACKEND=1 environment variable).
  • Separate out emscripten cache structure to asmjs and wasm directories.
  • Fix a bug where Emscripten would spawn too many unused python subprocesses (#4158)
  • Optimize Emscripten for large asm.js projects.
  • Added sdl2_net to Emscripten ports.
  • Updated to latest version of the SIMD polyfill (#4165)
  • Fixed an issue with missing texture formats support in GLES 3 (#4176)
  • Added a new WebAssembly linker option -s BINARYEN_IMPRECISE=1 (default=0) which mutes potential traps from WebAssembly int div/rem by zero and float-to-int conversions.
  • Added support for EXT_color_buffer_float extension.
  • Fixed behavior of SSE shift operations (#4165).
  • Fixed a bug where ctor_evaller.py (-Oz builds) would hang on Windows.
  • Fixed a bug where emscripten_set_main_loop() with EM_TIMING_SETTIMEOUT would incorrectly compute the delta times (#4200, #4208)
  • Update pthreads support to latest proposed spec version. (#4212, #4220)
  • Fixed an unresolved symbol linker error in embind (#4225)
  • Fix file_packager.py --use-preload-cache option to also work on Safari and iOS (#2977, #4253)
  • Added new file packager option --indexedDB-name to allow specifying the database name to use for the cache (#4219)
  • Added DWARF style debugging information.
  • Full list of changes:

v1.36.1: 3/8/2016

  • Fixed glfwSetWindowSizeCallback to conform to GLFW2 API.
  • Update OpenAL sources only when the browser window is visible to avoid occasional stuttering static glitches when the page tab is hidden. (#4107)
  • Implemented LLVM math intrinsics powi, trunc and floor.
  • Added support for SDL_GL_ALPHA_SIZE in GL context initialization. (#4125)
  • Added no-op stubs for several pthread functions when building without pthreads enabled (#4130)
  • Optimize glUniformfv and glVertexAttribfv functions to generate less garbage and perform much faster (#4128)
  • Added new EVAL_CTORS optimization pass which evaluates global data initializer constructors at link time, which would improve startup time and reduce code size of these ctors.
  • Implemented support for OpenAL AL_PITCH option.
  • Implemented new build options -s STACK_OVERFLOW_CHECK=0/1/2 which adds runtime stack overrun checks. 0: disabled, 1: minimal, between each frame, 2: at each explicit JS side stack allocation call to allocate().
  • Fixed an issue with -s SPLIT_MEMORY mode where an unsigned 32-bit memory access would come out as signed. (#4150)
  • Fixed asm.js validation in call handlers to llvm_powi_f*.
  • Full list of changes:

v1.36.0: 2/23/2016

  • Fixed an OpenAL bug where OpenAL sources would not respect global volume setting.
  • Fixed an issue where alGetListenerf() with AL_GAIN would not return the correct value. (#4091)
  • Fixed an issue where setting alListenerf() with AL_GAIN would not set the correct value. (#4092)
  • Implemented new JS optimizer "Duplicate Function Elimination" pass which collapses identical functions to save code size.
  • Implemented the _Exit() function.
  • Added support for SSE3 and SSSE3 intrinsics (#4099) and partially for SSE 4.1 intrinsics (#4030, #4101)
  • Added support for -include-pch flag (#4086)
  • Fixed a regex syntax in ccall on Chrome Canary (#4111)
  • Full list of changes:

v1.35.23: 2/9/2016

  • Provide $NM environment variable to point to llvm-nm when running emconfigure, which helps e.g. libjansson to build (#4036)
  • Fixed glGetString(GL_SHADING_LANGUAGE_VERSION) to return appropriate result depending on if running on WebGL1 vs WebGL2, instead of hardcoding the result (#4040)
  • Fixed a regression with CMake try_run() possibly failing, caused by the addition of CMAKE_CROSSCOMPILING_EMULATOR in v1.32.3.
  • Fixed CMake to work in the case when NODE_JS is an array containing parameters to be passed to Node.js. (#4045)
  • Fixed a memory issue that caused the Emscripten memory initializer file (.mem.js) to be unnecessarily retained in memory during runtime (#4044)
  • Added support for complex valued mul and div ops.
  • Added new option "Module.environment" which allows overriding the runtime ENVIRONMENT_IS_WEB/ENVIRONMENT_IS_WORKER/ENVIRONMENT_IS_NODE/ENVIRONMENT_IS_SHELL fields.
  • Fixed an issue with SAFE_HEAP methods in async mode (#4046)
  • Fixed WebSocket constructor to work in web worker environment (#3849)
  • Fixed a potential issue with some browsers reporting gamepad axis values outside [-1, 1] (#3602)
  • Changed libcxxabi to be linked in last, so that it does not override weakly linked methods in libcxx (#4053)
  • Implemented new JSDCE code optimization pass which removes at JS link stage dead code that is not referenced anywhere (in addition to LLVM doing this for C++ link stage).
  • Fixed a Windows issue where embedding memory initializer as a string in JS code might cause corrupted output. (#3854)
  • Fixed an issue when spaces are present in directory names in response files (#4062)
  • Fixed a build issue when using --tracing and -s ALLOW_MEMORY_GROWTH=1 simultaneously (#4064)
  • Greatly updated Emscripten support for SIMD.js intrinsics (non-SSE or NEON)
  • Fixed an issue where compiler would not generate a link error when JS library function depended on a nonexisting symbol. (#4077)
  • Removed UTF16 and UTF32 marshalling code from being exported by default.
  • Removed the -s NO_BROWSER linker option and automated the detection of when that option is needed.
  • Removed the JS implemented C++ symbol name demangler, now always depend on the libcxxabi compiled one.
  • Fixed an issue where Emscripten linker would redundantly generate missing function stubs for some functions that do exist.
  • Full list of changes:

v1.35.22: 1/13/2016

v1.35.21: 1/13/2016

v1.35.20: 1/10/2016

  • Fixed -s USE_PTHREADS compilation mode to account that SharedArrayBuffer specification no longer allows futex waiting on the main thread. (#4024)
  • Added new python2 vs python3 compatibility wrappers for emcmake, emconfigure, emmake and emar.
  • Fixed atomicrmw i64 codegen (#4025)
  • Optimized codegen to simplify "x != 0" to just "x" when output is a boolean.
  • Fixed a compiler crash when generating atomics code in debug builds of LLVM.
  • Fixed a compiler crash when generating SIMD.js code that utilizes non-canonical length vectors (e.g. <float x 3>)
  • Full list of changes:

v1.35.19: 1/7/2016

v1.35.18: 1/7/2016

v1.35.17: 1/4/2016

v1.35.16: 1/4/2016

v1.35.15: 1/4/2016

  • Fixed an error with glClearbufferfv not working. (#3961)
  • Improved file packager code so that file:// URLs work in Chrome too (#3965)
  • Fixed issues with the --memoryprofiler UI.
  • Fixed a Windows issue when generating system libraries in cache (#3939)
  • Fixed a regression from v1.35.13 where GLES2 compilation would not work when -s USE_PTHREADS=1 was passed.
  • Added support for WebIDL arrays as input parameters to WebIDL binder.
  • Updated build support when using the LLVM wasm backend.
  • Added new linker option --threadprofiler which generates a threads dashboard on the generated page for threads status overview. (#3971)
  • Improved backwards compatibility of building on GCC 4.3 - 4.6.
  • Fixed an asm.js validation issue when building against updated SIMD.js specification. (#3986)
  • Improved Rust support.
  • Full list of changes:

v1.35.14: 12/15/2015

v1.35.13: 12/15/2015

  • Updated -s USE_PTHREADS code generation to reflect that the SharedInt*Array hierarchy no longer exists in the SharedArrayBuffer spec.
  • Removed references to Atomic.fence() which no longer is part of the SharedArrayBuffer specification.
  • Fixed an issue where JS code minifiers might generate bad code for cwrap (#3945)
  • Updated compiler to issue a warning when --separate-asm is being used and output suffix is .js.
  • Added new build option -s ONLY_MY_CODE which aims to eliminate most of the Emscripten runtime and generate a very minimal compiler output.
  • Added new build option -s WASM_BACKEND=0/1 which controls whether to utilize the upstream LLVM wasm emitting codegen backend.
  • Full list of changes:

v1.35.12: 11/28/2015

v1.35.11: 11/27/2015

v1.35.10: 11/25/2015

  • Integration with Binaryen.
  • Add a performance warning when multiple FS.syncfs() calls are in flight simultaneously.
  • Correctly pass GLFW_REPEAT when sending key press repeats.
  • Improved filesystem performance when building in multithreaded mode (#3923)
  • Improve error detection when data file fails to load.
  • Clarified that -s NO_DYNAMIC_EXECUTION=1 and -s RELOCATABLE=1 build modes are mutually exclusive.
  • Added new build option -s NO_DYNAMIC_EXECUTION=2 which demotes eval() errors to warnings at runtime, useful for iterating fixes in a codebase for multiple eval()s (#3930)
  • Added support to Module.locateFile(filename) to locate the pthread-main.js file (#3500)
  • Changed -s USE_PTHREADS=2 and -s PRECISE_F32=2 to imply --separate-asm instead of requiring it, to be backwards compatible (#3829, #3933)
  • Fixed bad codegen for some 64-bit atomics (#3892, #3936)
  • When emitting NaN canonicalization warning, also print the location in code where it occurs.
  • Full list of changes:

v1.35.9: 11/12/2015

v1.35.8: 11/10/2015

  • Removed obsoleted EXPORTED_GLOBALS build option.
  • Export filesystem as global object 'FS' in Emscripten runtime.
  • Fixed realpath() function on directories.
  • Fixed round() and roundf() to work when building without -s PRECISE_F32=1 and optimize these to be faster (#3876)
  • Full list of changes:

v1.35.7: 11/4/2015

v1.35.6: 11/4/2015

  • This tag was created for technical purposes, and has no changes compared to v1.35.6.

v1.35.5: 11/4/2015

  • Removed Content-Length and Connection: close headers in POST requests.
  • Migrate to using the native C++11-implemented optimizer by default.
  • Fixed call to glDrawBuffers(0, *); (#3890)
  • Fixed lazy file system to work with closure (#3842)
  • Fixed gzip compression with lazy file system (#3837)
  • Added no-op gracefully failing stubs for process spawn functions (#3819)
  • Clarified error message that memory growth is not supported with shared modules (#3893)
  • Initial work on wasm support in optimizer
  • Full list of changes:

v1.35.4: 10/26/2015

v1.35.3: 10/26/2015

v1.35.2: 10/20/2015

v1.35.1: 10/20/2015

v1.35.0: 10/19/2015

v1.34.12: 10/13/2015

  • Added new experimental build option -s SPLIT_MEMORY=1, which splits up the Emscripten HEAP to multiple smaller slabs.
  • Added SDL2_ttf to Emscripten ports.
  • Added support for building GLES3 code to target WebGL 2. (#3757, #3782)
  • Fixed certain glUniform*() functions to work properly when called in conjunction with -s USE_PTHREADS=1.
  • Fixed support for -l, -L and -I command line parameters to accept a space between the path, i.e. "-l SDL". (#3777)
  • Fixed SSE2 support in optimized builds.
  • Changed the default behavior of warning when absolute paths are passed to -I to be silent. To enable the absolute paths warning, pass "-Wwarn-absolute-paths" flag to emcc.
  • Added new linker option -s ABORTING_MALLOC=0 that can be used to make malloc() return 0 on failed allocation (Current default is to abort execution of the page on OOM) (#3822)
  • Removed the default behavior of automatically decoding all preloaded assets on page startup (#3785)
  • Full list of changes:

v1.34.11: 9/29/2015

v1.34.10: 9/25/2015

  • Added wasm compressor/decompressor polyfill (#3766)
  • Added support for sRGB texture formats.
  • Removed the deprecated --compression option.
  • Fixed an issue with asm.js validation for pthreads being broken since v1.34.7 (#3719)
  • Added built-in cpu performance profiler, which is enabled with linker flag --cpuprofiler. (#3781)
  • Added build-in memory usage profiler, which is enabled with linker flag --memoryprofiler. (#3781)
  • Fixed multiple arities per EM_ASM block (#3804)
  • Fixed issues with SSE2 an NaN bit patterns. (emscripten-fastcomp #116)
  • Full list of changes:

v1.34.9: 9/18/2015

  • Fixed an issue with --llvm-lto 3 builds (#3765)
  • Optimized LZ4 compression
  • Fixed a bug where glfwCreateWindow would return success even on failure (#3764)
  • Greatly optimized the -s SAFE_HEAP=1 linker flag option by executing the heap checks in asm.js side instead.
  • Fixed the return value of EM_ASM_DOUBLE (#3770)
  • Implemented getsockname syscall (#3769)
  • Don't warn on unresolved symbols when LINKABLE is specified.
  • Fixed various issues with SSE2 compilation in optimized builds.
  • Fixed a breakage with -s USE_PTHREADS=2 (#3774)
  • Added support for GL_HALF_FLOAT in WebGL 2. (#3790)
  • Full list of changes:

v1.34.8: 9/9/2015

  • Fixed a race condition at worker startup (#3741)
  • Update emrun to latest, which improves unit test run automation with emrun.
  • Added support for LZ4 compressing file packages, used with the -s LZ4=1 linker flag. (#3754)
  • Fixed noisy build warning on "unexpected number of arguments in call to strtold" (#3760)
  • Added new linker flag --separate-asm that splits the asm.js module and the handwritten JS functions to separate files.
  • Full list of changes:

v1.34.7: 9/5/2015

v1.34.6: 8/20/2015

v1.34.5: 8/18/2015

  • Added Bullet physics, ogg and vorbis to emscripten-ports.
  • Added FreeType 2.6 to emscripten-ports.
  • Fixed CMake handling when building OpenCV.
  • Fixed and issue with exceptions being thrown in empty glBegin()-glEnd() blocks (#3693)
  • Improved function pointer handling between dynamically linked modules
  • Fixed some OpenAL alGetSource get calls (#3669)
  • Fixed issues with building the optimizer on 32-bit Windows (#3673)
  • Increased optimizer stack size on Windows to 10MB (#3679)
  • Added support for passing multiple input files to opt, to speed up optimization and linking in opt.
  • Full list of changes:

v1.34.4: 8/4/2015

  • Add special handling support for /dev/null as an input file (#3552)
  • Added basic printf support in NO_FILESYSTEM mode (#3627)
  • Update WebVR support to the latest specification, and add support for retrieving device names
  • Improved --proxy-to-worker build mode with proxying (#3568, #3623)
  • Generalized EXPORT_FS_METHODS to EXPORT_RUNTIME_METHODS
  • Added node externs for closure
  • Fixed a memory allocation bug in pthreads code (#3636)
  • Cleaned up some debug assertion messages behind #ifdef ASSERTIONS (#3639)
  • Fixed umask syscall (#3637)
  • Fixed double alignment issue with formatStrind and emscripten_log (#3647)
  • Added new EXTRA_EXPORTED_RUNTIME_METHODS build option
  • Updated emrun to latest version
  • Full list of changes:

v1.34.3: 7/15/2015

v1.34.2: 7/14/2015

  • Upgrade to new SIMD.js polyfill version and improved SIMD support.
  • Improved WebGL support in --proxy-to-worker mode (#3569)
  • Removed warning on unimplemented JS library functions
  • Fix WebGL 2 support with closure compiler
  • Fixed an issue with WebRTC support (#3574)
  • Fixed emcc to return a correct error process exit code when invoked with no input files
  • Fixed a compiler problem where global data might not get aligned correctly for SIMD.
  • Fixed a LLVM backend problem which caused recursive stack behavior when linking large codebases, which was seen to cause a stack overflow crash on Windows.
  • Full list of changes:

v1.34.1: 6/18/2015

v1.34.0: 6/16/2015

v1.33.2: 6/9/2015

v1.33.1: 6/3/2015

v1.33.0: 5/29/2015

v1.32.4: 5/16/2015

v1.32.3: 5/15/2015

v1.32.2: 5/8/2015

v1.32.1: 5/2/2015

v1.32.0: 4/28/2015

  • Compile .i files properly as C and not C++ (#3365).
  • Removed old deprecated options -s PRECISE_I32_MUL, CORRECT_ROUNDINGS, CORRECT_OVERFLOWS, CORRECT_SIGNS, CHECK_HEAP_ALIGN, SAFE_HEAP_LINES, SAFE_HEAP >= 2, ASM_HEAP_LOG, SAFE_DYNCALLS, LABEL_DEBUG, RUNTIME_TYPE_INFO and EXECUTION_TIMEOUT, since these don't apply to fastcomp, which is now the only enabled compilation mode.
  • Preliminary work towards supporting dynamic linking and dlopen().
  • Fixed an issue where emrun stripped some characters at output (#3394).
  • Fixed alignment issues with varargs.
  • Full list of changes:

v1.31.3: 4/22/2015

v1.31.2: 4/20/2015

v1.31.1: 4/17/2015

v1.31.0: 4/14/2015

v1.30.6: 4/14/2015

  • Removed support for the deprecated jcache functionality (#3313).
  • Added support to emscripten_GetProcAddress() to fetch symbols with the ANGLE suffix (#3304, #3315).
  • Added immintrin.h header file to include all SSE support.
  • Added an async option to ccall (#3307).
  • Stopped from using 0 as a valid source ID for OpenAL (#3303).
  • When project has disabled exception catching, build an exceptions-disabled version of libcxx.
  • Split libcxx into two parts to optimize code size for projects that only need small amount of libcxx (#2545, #3308).
  • Avoid fprintf usage in emscripten_GetProcAddress() to allow using it with -s NO_FILESYSTEM=1 (#3327).
  • Removed old deprecated functionalities USE_TYPED_ARRAYS, FHEAP, GC emulation and non-asmjs-emscripten ABI.
  • Don't refer to prefixed GL extensions when creating a GL context (#3324).
  • Removed support code for x86_fp80 type (#3341).
  • Optimize EM_ASM() calls even more (#2596).
  • Full list of changes:

v1.30.5: 4/7/2015

v1.30.4: 4/3/2015

v1.30.3: 4/3/2015

v1.30.2: 4/1/2015

v1.30.1: 3/24/2015

v1.30.0: 3/24/2015

  • Fixed a bug where html5.h API would not remove event handlers on request.
  • Fixed a regression issue that broke building on Windows when attempting to invoke tools/gen_struct_info.py.
  • Improved memory growth feature to better handle growing to large memory sizes between 1GB and 2GB (#3253).
  • Fixed issues with emrun with terminating target browser process, managing lingering sockets and command line quote handling.
  • Fixed a bug where unsigned integer return values in embind could be returned as signed (#3249).
  • Improved handling of lost GL contexts.
  • Changed malloc to be fallible (return null on failure) when memory growth is enabled (#3253).
  • Fixed a bug with WebIDL not being able to handle enums (#3258).
  • Updated POINTER_MASKING feature to behave as a boolean rather than a mask (#3240).
  • Improved "emcmake cmake" on Windows to automatically remove from path any entries that contain sh.exe in them, which is not supported by CMake.
  • Fixed an issue with symlink handling in readlink (#3277).
  • Updated SDL2 port to version 6.
  • Removed the obsolete FAST_MEMORY build option.
  • Added reciprocalApproximation and reciprocalSqrtApproximation SIMD intrinsics.
  • Full list of changes:

v1.29.12: 3/15/2015

  • Fix a bug where SDL_malloc and SDL_free were not available. (#3247)
  • Fix various issues with emrun usage. (#3234)
  • Fixed an off-by-one memory access in native optimizer.
  • Improve emterpreter support.
  • Full list of changes:

v1.29.11: 3/11/2015

  • Remove the requirement to pass -s PRECISE_F32=1 manually when building with SIMD support.
  • Fix a temp directory leak that could leave behind empty directories in the temp directory after build (#706)
  • Improve support for growable Emscripten heap in asm.js mode.
  • Added a warning message when generating huge asset bundles with file packager.
  • Fixed a bug where emscripten_get_gamepad_status might throw a JS exception if called after a gamepad was disconnected.
  • Improve emterpreter sleep support.
  • Optimize code generation when multiple consecutive bitshifts are present.
  • Optimize redundant stack save and restores, and memcpy/memsets.
  • Full list of changes:

v1.29.10: 2/19/2015

  • Add a warning message when generating code that has a very large number of variables, which optimization flags could remove.
  • Improve support for SIMD casts and special loads.
  • Fix the process return code when using EMCONFIGURE_JS=1.
  • Improved the error message in abort().
  • Fix main loop handling during emterpreter sync save/load.
  • Handle emscripten_async_call and friends during sleep, by pausing all safeSet*() operations.
  • Add support for Google WTF when building with --tracing.
  • Improve emterpreter stability with fuzzing.
  • Add an option to load the memory initializer file from a typed array (#3187)
  • Remove linker warning message when linking to -lm, since Emscripten includes musl that implements the math libraries built-in.
  • Add support for SDL_WM_SetCaption(), which calls to Module['setWindowTitle'], or if not present, sets the web page title. (#3192)
  • Full list of changes:

v1.29.9: 2/9/2015

  • Documented FORCE_ALIGNED_MEMORY to be no longer supported.
  • Fixes issues with native optimizer handling of "if () else {}" statements. (#3129)
  • Improved cross-browser support for EMSCRIPTEN_FULLSCREEN_FILTERING_NEAREST. (#3165)
  • Added new linker option --profiling-funcs, which generates output that is otherwise minified, except that function names are kept intact, for use in profilers and getting descriptive call stacks.
  • The Module object is no longer written in global scope. (#3167)
  • Added new emscripten_idb_* API. (#3169)
  • Added new function emscripten_wget_data().
  • Add support for GL_RED with GLES3/WebGL2. (#3176)
  • Added basic WebVR support. (#3177)
  • Full list of changes:

v1.29.8: 1/31/2015

v1.29.7: 1/28/2015

v1.29.6: 1/23/2015

  • Fixed an issue where calling glGen*() when the GL context was lost might throw a JS exception, instead a GL_INVALID_OPERATION is now recorded.
  • Improve label handling in native optimizer.
  • Full list of changes:

v1.29.5: 1/23/2015

  • Enable compiling source files with the extension ".c++".
  • Enable versioning of the emscripten ports so that older Emscripten versions can keep using older versions of the ports (#3144)
  • Added a whitelist option to emterpreter, a linker flag of form -s EMTERPRETIFY_WHITELIST=["symbol1","symbol2"]. (#3129)
  • Improved emscripten_get_pointerlock_status() to always fill the output structure even when pointer lock is not supported.
  • Added an environment variable EMCC_NO_OPT_SORT=0/1 option to configure whether the generated output should have the functions sorted by length, useful for debugging.
  • Added new tool tools/merge_pair.py which allows bisecting differences between two output files to find discrepancies.
  • Improved parsing in cashew.
  • Improved output message from emconfigure and emmake when inputs are unexpected.
  • Added built-in asm handler for LLVM fabs operation.
  • Full list of changes:

v1.29.4: 1/21/2015

  • Added new C <-> JS string marshalling functions asciiToString(), stringToAscii(), UTF8ToString(), stringToUTF8() that can be used to copy strings across the JS and C boundaries. (#2363)
  • Added new functions lengthBytesUTF8(), lengthBytesUTF16() and lengthBytesUTF32() to allow computing the byte lengths of strings in different encodings. (#2363)
  • Upgraded SDL2 port to version 4.
  • Add support for saving the emterpreter stack when there are functions returning a value on the stack (#3129)
  • Notice async state in emterpreter trampolines (#3129)
  • Optimize SDL1 pixel copying to the screen.
  • Fixed an issue with emterpreter parsing. (#3141)
  • Fixed an issue with native optimizer and -s PPRECISE_F32=1.
  • Full list of changes:

v1.29.3: 1/16/2015

v1.29.2: 1/16/2015

  • Fixed an issue with embind compilation in LLVM 3.5.
  • Fixed an issue with SDL audio queueing stability, which would queue audio too eagerly and cause stutter in some applications (#3122, #3124)
  • Enabled native JS optimizer to be built automatically on Windows, requires VS2012 or VS2013.
  • Improve error message to reflect the fact that DLOPEN_SUPPORT is currently not available (#2365)
  • Improve SIMD load and store support.
  • Upgraded SDL2 port to version 3.
  • Fix a bug with native JS optimizer and braces in nested ifs.
  • Improved emterpreter support.
  • Fixed LLVM 3.5 to build with Visual Studio on Windows (emscripten-fastcomp #61)
  • Full list of changes:

v1.29.1: 1/7/2015

v1.29.0: 1/7/2015

v1.28.3: 1/4/2015

v1.28.2: 12/17/2014

v1.28.1: 12/15/2014

v1.28.0: 12/12/2014

v1.27.2: 12/10/2014

v1.27.1: 11/20/2014

v1.27.0: 11/20/2014

v1.26.1: 11/7/2014

v1.26.0: 10/29/2014

v1.25.2: 10/16/2014

  • Fixed a bug in tmpfile() function not allocating the mode argument correctly.
  • Fixed a bug with handling empty files in IDBFS (#2845)
  • Added an implementation of the utimes() function (#2845)
  • Added experimental WebGL 2.0 support with the linker flag -s USE_WEBGL2=1. (#2873)
  • Fixed a UnboundTypeError occurring in embind (#2875)
  • Fixed an error "IndexSizeError: Index or size is negative or greater than the allowed amount" being thrown by Emscripten SDL 1.2 surface blit code. (#2879)
  • Fixed a JS minifier issue that generated "x--y from x - -y" (#2869)
  • Added a new emcc command line flag "--cache " to control the location of the Emscripten cache directory (#2816)
  • Implemented SDL_ConvertSurface() and added support for SDL_SRCALPHA in SDL_SetAlpha (#2871)
  • Fixed issues with the GL library handling of invalid input values.
  • Optimized SDL copyIndexedColorData function (#2890)
  • Implemented GLES3 emulation for glMapBufferRange() for upcoming WebGL 2 support, using the -s FULL_ES3=1 linker option.
  • Fixed a bug where setting up and cancelling the main loop multiple times would stack up the main loop to be called too frequently (#2839)
  • Introduced a new API emscripten_set_main_loop_timing() for managing the Emscripten main loop calling frequency (#2839)
  • Added new optimization flags SDL.discardOnLock and SDL.opaqueFrontBuffer to Emscripten SDL 1.2 SDL_LockSurface() and SDL_UnlockSurface() (#2870)
  • Fixed a bug with glfwGetProcAddress().
  • Added option to customize GLOBAL_BASE (the starting address of global variables in the Emscripten HEAP).
  • Added the ability to register mouseover and mouseout events from the HTML5 API.
  • Improved experimental SIMD support.
  • Full list of changes:

v1.25.1: 10/1/2014

v1.25.0: 9/30/2014

v1.24.1: 9/27/2014

  • Fixed issues with the tmpnam and tmpfile functions (#2797, 2798)
  • Fixed CMake package find code to not search any system directories, because Emscripten is a cross-compiler.
  • Improved support for the proposed solution for heap resizing.
  • Fixed an issue where one could not run a main loop without having first a GL context created when -s FULL_ES2 or -s LEGACY_GL_EMULATION were set.
  • For compatibility, Emscripten will no longer warn about missing library files for -lGL, -lGLU and -lglut libraries, since Emscripten provides the implementation for these without having to explicitly link to anything.
  • Added support for readonly (const) attributes and automatically call Pointer_stringify on DOMStrings in WebIDL.
  • Improved SIMD support for the experimental Ecmascript SIMD spec.
  • Added support for GLFW 3.0.
  • Added new Emscripten HTML 5 functions emscripten_set_mouseenter_callback() and emscripten_set_mouseleave_callback().
  • Emscripten now recognizes an environment variable EMCC_JSOPT_BLACKLIST=a,b,c,d which can be used to force-disable Emscripten to skip running specific JS optimization passes. This is intended as a debugging aid to help zoom in on JS optimizer bugs when compiling with -O1 and greater. (#2819)
  • Fixed a bug where Module['TOTAL_STACK'] was ignored (#2837).
  • Improved SIMD support for the experimental Ecmascript SIMD spec. Preliminary asm.js validation.
  • Full list of changes:

v1.24.0: 9/16/2014

v1.23.5: 9/12/2014

  • Added new functions emscripten_get_device_pixel_ratio(), emscripten_set_canvas_css_size() and emscripten_get_canvas_css_size() which allow handling High DPI options from C code.
  • Fixed bugs with timzone-related functions in the JS-implemented C standard library.
  • Implemented clock_gettime(CLOCK_MONOTONIC) and added a new function emscripten_get_now_is_monotonic() to query whether the JS-provided timer is monotonic or not.
  • Fixed an issue where the user could not pass --llvm-opts=xxx when also specifying --llvm-lto=2.
  • Renamed the linker option -profiling to --profiling for consistency. The old form is still supported.
  • Formalized the set of valid characters to be used in files passed to the file_packager.py (#2765).
  • Implemented SDL function SDL_BlitScaled.
  • Fixed a bug with right modifier keys in SDL.
  • Full list of changes:

v1.23.4: 9/7/2014

v1.23.3: 9/7/2014

  • Removed the scons-tools SCons build system as unused.
  • Fixed an issue where applications could not handle WebGL context creation failures gracefully.
  • Fixed a bug where the stringToC function in ccall/cwrap might not allocate enough space to hold unicode strings.
  • Removed CMake from attempting to link to library -ldl when building projects, by unsetting CMAKE_DL_LIBS.
  • Fixed a bug where write_sockaddr might return undefined data in its output structure.
  • Added a new experimental -s POINTER_MASKING=1 linker option that might help JS VMs to optimize asm.js code.
  • Added first version of a memory tracing API to profile memory usage in Emscripten applications.
  • Added functions glob and globfree from musl regex library.
  • Improved SIMD support for the experimental Ecmascript SIMD spec.
  • Full list of changes:

v1.23.2: 9/2/2014

  • Adjusted the process and group ids reported by the stub library functions to be closer to native unix values.
  • Set stack to be aligned to 16 bytes. (#2721)
  • Fixed a compiler error "unresolved symbol: __cxa_decrement_exception_refcount" (#2715)
  • Added a new warning message that instructs that building .so, .dll and .dylib files is not actually supported, and is faked for compatibility reasons for existing build chains. (#2562)
  • Fixed problems with SDL mouse scrolling (#2643)
  • Implemented OpenAL function alSourceRewind.
  • Removed several old header files from the Emscripten repository that had been included for emulation purposes (zlib.h, png.h, tiff.h, tiffio.h), but their implementation is not included.
  • Work around an issue in d8 with binary file reading that broke e.g. printf when running in d8. (#2731)
  • Rigidified the semantics of Module.preRun and Module.postRun: These must always be JS arrays, single functions are not allowed (#2729)
  • Improved compiler warning diagnostics when generating output that will not validate as asm.js (#2737)
  • Updated to latest emrun version to enable support for passing arguments with hyphens to the program. (#2742)
  • Added Bessel math functions of the first kind (j0, j1, jn) from musl.
  • Improved SIMD support for the experimental Ecmascript SIMD spec.
  • Full list of changes:

v1.23.1: 8/26/2014

  • Add support for the Chrome variant of the Gamepad API.
  • Updates to SIMD.js support.
  • Implemented glutSetCursor function.
  • Added new link-time options -s NO_FILESYSTEM=1 and -s NO_BROWSER=1 to enable reducing output file sizes when those functionalities are not necessary.
  • Added a new option --closure 2 to allow running closure even on the asm.js output.
  • Fixed a regression bug that broke the use of emscripten_set_socket_error_callback() in emscripten.h
  • Removed the support for old discontinued Mozilla Audio Data API in src/library_sdl.js.
  • Removed the support for using Web Audio ScriptProcessorNode to stream audio.
  • Improved SDL audio streaming by using the main rAF() callback instead of a separate setTimeout() callback to schedule the audio data.
  • Deprecated compiling without typed arrays support.
  • Migrated to using musl PRNG functions. Fixes reported bugs about the quality of randomness (#2341)
  • Improved SIMD support for the experimental Ecmascript SIMD spec.
  • Full list of changes:

v1.23.0: 8/21/2014

  • Added support for array attributes in WebIDL bindings.
  • Allow cloning pointers that are scheduled for deletion in embind, and add support for null in embind_repr().
  • Fixed possible issues with rounding and flooring operations.
  • Full list of changes:

v1.22.2: 8/19/2014

  • Adds stack overflow checks when building with the link flag -s ASSERTIONS=1.
  • Fix an issue where EM_ASM was not usable with closure when closure removed the Module object (#2639)
  • The locale "POSIX" is now recognized (#2636)
  • Fixed a problem with embind on IE11.
  • Added OpenAL functions alSource3i, alListener3f, alGetEnumValue and alSpeedOfSound and also recognize ALC_MAX_AUXILIARY_SENDS.
  • Fixed an issue where emcc would create .o files in the current directory when compiling multiple code files simultaneously (#2644)
  • The -s PROXY_TO_WORKER1= option now looks for a GET option "?noProxy" in the page URL to select at startup time whether proxying should be on or off.
  • Added new functions emscripten_yield, emscripten_coroutine_create and emscripten_coroutine_next which implement coroutines when building with the -s ASYNCIFY=1 option.
  • Optimized the size of intermediate generated .o files by omitting LLVM debug info from them when not needed. (#2657)
  • Fixed WebSocket connection URLs to allow a port number in them, e.g. "server:port/addr" (2610)
  • Added support for void* to the WebIDL binder, via the identifier VoidPtr.
  • Optimize emcc to not copy bitcode files around redundantly.
  • Fix stat() to correctly return ENOTDIR when expected (#2669).
  • Fixed issues with nested exception catching (#1714).
  • Increased the minimum size of the Emscripten HEAP to 64k instead of a previous 4k.
  • The {{{ cDefine('name') }}} macros now raise a compile-time error if the define name is not found, instead of hiding the error message inside the compiled output (#2672)
  • Fixed an issue where --emrun parameter was not compatible with the -s PROXY_TO_WORKER=1 option.
  • Improved WebGL support when compiling with the PROXY_TO_WORKER=1 option.
  • Fixed a regression issue with the handling of running dtors of classes that use virtual inheritance. (#2682)
  • Added an option Module.locateFilePackage() as a means to customize where data files are found in relative to the running page (#2680). NOTE: This parameter was later renamed to Module.locateFile() instead in release 1.24.0.
  • Fixed a bug where OpenAL sources would not properly delete.
  • Fixed a bug with upstream libc++ on std::map, std::multimap and std::unordered_map self-assignment (http://llvm.org/bugs/show_bug.cgi?id=18735)
  • Allow using asm volatile("": : :"memory") as a compile-time reordering barrier (#2647)
  • Full list of changes:

v1.22.1: 8/7/2014

  • Added support for prefixing functions with '$' in JS libraries, in order to cause them not be prefixed with '_' when compiling.
  • Improved WebIDL compiler to support enums.
  • Fixed a bug with emscripten_force_exit() that would throw an exception (#2629).
  • Fixed setlocale() when setting a bad locale. (#2630)
  • Fixed a compiler miscompilation bug when optimizing loops. (#2626)
  • Fixed an issue with rethrowing an exception (#2627)
  • Fixed a bug where malloc()ing from JS code would leak memory if the C/C++ side does not use malloc() (#2621)
  • Removed an unnecessary assert() in glReadPixels, and improved it to support more texture pixel types.
  • Fixed a bug with std::locale accepting unknown locale names (#2636)
  • Added support for WebIDL binder to work with Closure (#2620)
  • Added no-op SDL IMG_Quit() and TTF_Quit() symbols.
  • Migrated to building libcxx and libcxxapi with -Oz optimization flags.
  • Full list of changes:

v1.22.0: 8/5/2014

v1.21.10: 7/29/2014

  • Fixed a Windows-specific issue where the generated output files might contain line endings of form \r\r\n. This caused browser debuggers to get confused with line numbers. (#2133)
  • Improved the node.js workaround introduced in v1.21.8.
  • Implemented new HTML5 API for direct WebGL context creation, emscripten_webgl_*().
  • Fixed a bug when loading in node.js and loaded by another module (#2586)
  • Full list of changes:

v1.21.9: 7/28/2014

v1.21.8: 7/28/2014

v1.21.7: 7/25/2014

  • Added new environment variable EMCC_ONLY_FORCED_STDLIBS which can be used to restrict to only linking to the chosen set of Emscripten-provided libraries. (See also EMCC_FORCE_STDLIBS)
  • Adjusted argv[0] and environment variables USER, HOME, LANG and _ to report a more convenient set of default values. (#2565)
  • Fixed an issue where the application could not use environ without also referring to getenv() (#2557)
  • Fixed an issue with IDBFS running in web workers.
  • Print out an error if IDBFS is used without IDB support.
  • Fixed calling Runtime.getFuncWrapper() when -s ALIASING_FUNCTION_POINTERS=1 (#2010)
  • Fixed an issue where deleting files during directory iteration would produce incorrect iteration results (#2528)
  • Fixed support for strftime with %z and %Z (#2570)
  • Fixed a bug with truncate() throwing an exception (#2572)
  • Improved the linker to generate warning messages if user specifies -s X=Y linker flags that do not exist (#2579)
  • Fixed an issue with creating read-only files (#2573)
  • Added first implementation for the ASYNCIFY option, which splits up synchronous blocking loops to asynchronous execution. For more information on this approach, see https://github.com/emscripten-core/emscripten/wiki/Asyncify
  • Full list of changes:

v1.21.6: 7/22/2014

  • Separated OpenAL AL and ALC errors to properly separate fields.
  • When using EGL to initialize a GL context, initialize a stencil buffer to the context as well, since proper EGL context choosing is not yet implemented.
  • Added new linker flag -s DEMANGLE_SUPPORT to choose whether to compile the application with libcxxabi-provided demangling support ___cxa_demangle().
  • Fixed a problem where calling stat() on a nonexisting file in the runtime VFS would result in an exception being thrown. (#2552)
  • When using the -v flag, no longer retain intermediate compilation files. To preserve the intermediate files, set the EMCC_DEBUG=1 environment variable. (#2538)
  • Added a new HTML setting Module.memoryInitializerPrefixURL which specifies a prefix for where the memory initializer file .mem.js should be loaded from (#2542)
  • Implemented eglReleaseThread to work according to spec.
  • Implemented a new function emscripten_force_exit() which immediately shuts down the C runtime.
  • Fixed a bug with exception handling that resulted in an error unresolved symbol: _ZTISt13bad_exception (#2560)
  • Full list of changes:

v1.21.5: 7/21/2014

  • Added support for glDrawBuffers with the WEBGL_draw_buffers extension.
  • Added stub implementation for eglReleaseThread.
  • Fixed a bug where passing -E to emcc used the system include headers instead of the built-in ones. (#2534)
  • Fixed the stacktrace() function to work on MSIE as well.
  • Removed the zlib.h header file from system include directory, since Emscripten does not provide an implementation of zlib built-in.
  • Added support for __cxa_bad_typeid (#2547)
  • Fixed an internal compiler crash with a certain pattern involving optimized builds and int64_t (#2539)
  • Fixed an issue with -s EXCEPTION_CATCHING_WHITELIST handling where an extension that was a substring of another might get erroneously handled.
  • Full list of changes:

v1.21.4: 7/17/2014

  • Implemented the getsockopt() function.
  • Added new event callback functions emscripten_set_socket_xx_callback() that allow listening to WebSocket events in an asynchronous manner.
  • Greatly improved CMake support, now various forms of configure-time test builds are supported, and the default extension is set to ".js"
  • Prohibit the virtual filesystem from creating files with name '.' or '..' at runtime.
  • Have runtime mkdir() function call normalize the path to be created before creation.
  • Fixed an issue with omitting the third paramter in cwrap() call (#2511).
  • Fixed an issue where mouse event handling would throw an exception if the page did not contain a canvas object.
  • Fixed a GL initialization problem when user has extended Array with custom functions (#2514)
  • Added new compiler defines EMSCRIPTEN_major, EMSCRIPTEN_minor and EMSCRIPTEN_tiny which communicate the compiler version major.minor.tiny to compiled applications (#2343)
  • Fixed a bug where emrun did not properly capture the exit code when exit runtime via not calling exit().
  • Fixed an error message when symlinkin invalid filenams at runtime.
  • Fixed a bug in EGL context creation that parsed the input context creation parameters with wrong terminator.
  • Improved ffdb.py to be smarter when to attempt port forwarding to connect to a FFOS device DevTools port.
  • Implemented strsignal() function (#2532)
  • Full list of changes:

v1.21.3: 7/10/2014

  • Added implementations for SDL function SDL_AudioQuit and SDL_VideoQuit.
  • Fix an issue with the optimizeShifts optimization enabled in previous version.
  • Fixed the -s RELOOPER command line parameter to work.
  • Fixed a bug where building the system libc migt result in a compiler deadlock on Windows.
  • Removed emcc from trying to link in .dll files as static libraries on Windows.
  • Added support for GL_HALF_FLOAT_OES.
  • Fixed a bug where emcmake did not work on Windows.
  • Use multithreaded compilation to build libc.
  • Fixed an issue where the GL interop library could throw an exception in an error condition, instead of raising a GL error.
  • Full list of changes:

v1.21.2: 7/5/2014

  • Improved the checks that detect that code is run only while the runtime is initialized.
  • The memory initializer file (.mem.js) is now emitted by default when compiling with at least -O2 optimization level.
  • Fixed a performance issue where built-in math functions (Math.sqrt, etc.) took a slightly slower path (#2484).
  • Added support for the ffs libc function.
  • Re-enabled optimizeShifts optimization when not compiling for asm.js (#2481)
  • Full list of changes:

v1.21.1: 7/3/2014

v1.21.0: 7/2/2014

  • Enable memory init files (.mem) by default in optimized builds (-O2+), as if --memory-init-file 1 is specified. This makes the default behavior on optimized builds emit smaller and faster-to-load code, but does require that you ship both a .js and a .mem file (if you prefer not to, can use --memory-init-file 1 ).
  • Implemented new SDL 1.2 functions SDL_GetRGB, SDL_GetRGBA and SDL_putenv.
  • Added support for /dev/random, /dev/urandom and C++11 std::random_device, which will use cryptographically secure random api if available. (#2447)
  • Added support for CMake find_path() directive.
  • Added support for std::unique_ptr in embind.
  • Improved Windows support for ffdb.py.
  • Implemented the clip_rect structure for created SDL surfaces.
  • Fixed a regression with SDL touch events (#2466)
  • Added support for C++11 std::thread::hardware_concurrency which backs to navigator.hardwareConcurrency. See http://wiki.whatwg.org/wiki/Navigator_HW_Concurrency (#2456)
  • Optimized embind code generation with constexprs.
  • Enabled the use of Runtime.add&removeFunction when closure minification is active (#2446)
  • Implemented support for accessing WebGL when building via the proxy to worker architecture.
  • Full list of changes:

v1.20.0: 6/13/2014

  • Optimize in-memory virtual filesystem performance when serialized to an IndexedDB.
  • Fixed memcpy regression with ta0 and ta1 modes.
  • Fixed an issue with line numbers being messed up when generating source maps (#2410)
  • Fixed an ffdb logging bug that could cause it to drop messages if they were being received too fast. Added support getting memory and system descriptions with ffdb.
  • Added a new extension to SDL "emscripten_SDL_SetEventHandler()" which enabled application to perform SDL event handling inside a JS event handler to overcome browser security restrictions. (#2417)
  • Full list of changes:

v1.19.2: 6/9/2014

  • Updated CMake support for response file handling.
  • Fixed issues with glfwGetProcAddress and glfwSetWindowSizeCallback.
  • Fixed an issue with regexes that caused issues on IE11 runtime (#2400)
  • Added a new functions emscripten_get_preloaded_image_data() and emscripten_get_preloaded_image_data_from_FILE() to obtain pixel data of preloaded images.
  • Greatly improved ffdb capabilities to operate a FFOS device.
  • Fixed a Windows-specific bug where the user temp directory was littered with temporary .rsp files that did not get cleaned up.
  • Improved SIMD support.
  • Full list of changes:

v1.19.1: 6/3/2014

  • Migrate to using musl sscanf and sprintf and the family that writes to memory, and not directly to the filesystem.
  • Improve the error messages from -s SAFE_HEAP_ACCESS=1 runtime checks.
  • Added new linker flag -s NO_DYNAMIC_EXECUTION=1 which removes the use of eval() and new Function() in the generated output. For more information, see "Eval and related functions are disabled" in https://developer.chrome.com/extensions/contentSecurityPolicy .
  • Fixed a compiler issue when very large double constants are present. (#2392)
  • Full list of changes:

v1.19.0: 5/29/2014

  • Added an error message to signal that linkable modules are not supported in fastcomp.
  • Fixed a miscompilation issue that resulted in an error "SyntaxError: invalid increment operand" and a statement +(+0) being generated (#2314)
  • Make optimized compiler output smaller by running the shell code through uglify when not using closure.
  • Fixed a crash in SDL audio loading code introduced in v1.18.3
  • Fixed an issue where glTex(Sub)Image2D might throw an exception on error, instead of setting glGetError().
  • Added new typedefs emscripten_align1_short, emscripten_align{1/2}_int, emscripten_align{1/2}_float and emscripten_align{1/2/4}_double to ease signaling the compiler that unaligned data is present. (#2378)
  • Fixed an embind issue with refcount tracking on smart pointers.
  • Full list of changes:

v1.18.4: 5/27/2014

v1.18.3: 5/21/2014

v1.18.2: 5/19/2014

  • Fixed a problem which blocked user applications from handling WebGL context loss events themselves.
  • Added a new HTML5 api function emscripten_is_webgl_context_lost() which allows polling for context loss in addition to receiving events.
  • Improved async wget progress events to work better across browsers.
  • Improved WebIDL binder support.
  • Added new typeof() function to emscripten::val.
  • Added support for SDL window events SDL_WINDOWEVENT_FOCUS_GAINED, SDL_WINDOWEVENT_FOCUS_LOST, SDL_WINDOWEVENT_SHOWN, SDL_WINDOWEVENT_HIDDEN.
  • Fixed a compiler miscompilation on unsigned i1 bitcasts (#2350)
  • Fixed a compiler bug where doubles in varargs might not get 8-byte aligned (#2358)
  • Full list of changes:

v1.18.1: 5/12/2014

  • Fixed an issue where the mouse wheel scroll did not work with SDL.
  • Fixed an issue with emscripten_async_wget, which undesirably expected that the string pointer passed to it stayed alive for the duration of the operation (#2349)
  • Emscripten now issues a warning message when the EXPORTED_FUNCTIONS list contains invalid symbol names (#2338)
  • Full list of changes:

v1.18.0: 5/10/2014

v1.17.0: 5/6/2014

  • Enabled asm.js compilation and -s PRECISE_F32 support when using embind.
  • Improved relooper to emit switches in many-entried blocks.
  • Fixed a GLFW bug where mouse wheel direction was reversed.
  • Fixed glfwGetKey to work even when no callback is registered with glfwGetKeyCallback (#1320)
  • Added a new tool 'webidl_binder' that generates C <-> JS interop code from WebIDL descriptions.
  • Fix emscripten compilation to work on pages that don't contain a HTML canvas.
  • Added a new error message to default shell when an uncaught exception is thrown.
  • Improved error diagnostics reported by -s SAFE_HEAP=1.
  • Added support for registering callbacks hook to VFS file open, write, move, close and delete.
  • Added embind support to std::basic_string
  • By default, the C runtime will no longer exit after returning from main() when safeSetTimeout() or safeSetInterval() is used.
  • Fixed an issue with sscanf formatting (#2322)
  • Fixed an issue where precompiled headers were given a wrong output filename (#2320)
  • Enabled registerizeHarder optimization pass to work when outlining is enabled.
  • Fixed an issue with strptime month handling (#2324)
  • Added an initial implementation of a new tool 'ffdb' which can be used to operate a Firefox OS phone from the command line.
  • Fixed a compiler crash on assertion failure '!contains(BranchesOut, Target)' (emscripten-fastcomp #32)
  • Added a new ABI to Clang that targets Emscripten specifically. Stop aligning member functions to save some space in the function table array.
  • Full list of changes:

v1.16.0: 4/16/2014

v1.15.1: 4/15/2014

  • Added support for SDL2 touch api.
  • Added new user-controllable emdind-related define #define EMSCRIPTEN_HAS_UNBOUND_TYPE_NAMES, which allows optimizing embind for minimal size when std::type_info is not needed.
  • Fixed issues with CMake support where CMAKE_AR and CMAKE_RANLIB were not accessible from CMakeLists.txt files.
  • Full list of changes:

v1.15.0: 4/11/2014

v1.14.1: 4/8/2014

  • Added new command line utility 'emcmake', which can be used to call emconfigure for cmake.
  • Added a new emcc command line parameter '--valid-abspath', which allows selectively suppressing warning messages that occur when using absolute path names in include and link directories.
  • Added a new emcc linker command line parameter '--emit-symbol-map', which will save a map file between minified global names and the original function names.
  • Fixed an issue with --default-object-ext not always working properly.
  • Added optimizations to eliminate redundant loop variables and redundant self-assignments.
  • Migrated several libc functions to use compiled code from musl instead of handwritten JS implementations.
  • Improved embind support.
  • Renamed the EM_ASM_() macro to the form EM_ASM_ARGS().
  • Fixed mouse button ordering issue in glfw.
  • Fixed an issue when creating a path name that ends in a slash (#2258, #2263)
  • Full list of changes:

v1.14.0: 3/25/2014

  • Added new emcc linker command line option '-profiling', which defaults JS code generation options suited for benchmarking and profiling purposes.
  • Implemented the EGL function eglWaitGL().
  • Fixed an issue with the HTML5 API that caused the HTML5 event listener unregistration to fail.
  • Fixed issues with numpad keys in SDL support library.
  • Added a new JS optimizer pass 'simplifyIfs', which is run when -s SIMPLIFY_IFS=1 link flag is set and -g is not specified. This pass merges multiple nested if()s together into single comparisons, where possible.
  • Removed false positive messages on missing internal "emscripten_xxx" symbols at link stage.
  • Updated to latest relooper version.
  • Full list of changes:

v1.13.2: 3/15/2014

v1.13.1: 3/10/2014

v1.13.0: 3/3/2014

  • Fixed the deprecated source mapping syntax warning.
  • Fixed a buffer overflow issue in emscripten_get_callstack (#2171).
  • Added support for -Os (optimize for size) and -Oz (aggressively optimize for size) arguments to emcc.
  • Fixed a typo that broko the call signature of glCompressedTexSubImage2D() function (#2173).
  • Added new browser fullscreen resize logic that always retains aspect ratio and adds support for IE11.
  • Improve debug messaging with bad function pointer calls when -s ASSERTIONS=2 is set.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.12.3...1.13.0

v1.12.3: 2/27/2014

  • Fixed alcOpenDevice on Safari.
  • Improved the warning message on missing symbols to not show false positives (#2154).
  • Improved EmscriptenFullscreenChangeEvent HTML5 API structure to return information about HTML element and screen sizes for convenience.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.12.2...1.12.3

v1.12.2: 2/25/2014

v1.12.1: 2/25/2014

  • TURNED ON FASTCOMP BY DEFAULT. This means that you will need to migrate to fastcomp-clang build. Either use an Emscripten SDK distribution, or to build manually, see http://kripken.github.io/emscripten-site/docs/building_from_source/LLVM-Backend.html for info.
  • Migrate to requiring Clang 3.3 instead of Clang 3.2. The fastcomp-clang repository by Emscripten is based on Clang 3.3.
  • Deprecated old Emscripten libgc implementation.
  • asm.js will now be always enabled, even in -O0 builds in fastcomp.
  • Remove support for -s RUNTIME_TYPE_INFO, which is unsupported in fastcomp.
  • Added a new "powered by Emscripten" logo.
  • Updated default shell.html graphical layout.
  • Added new macro EM_ASM_, which allows sending values to JS without returning anything.
  • Deprecated the jcache compiler option. It should not be needed anymore.
  • Added support for fetching callstack column information in Firefox 30 in emscripten_get_callstack.
  • Fix issues with missing exceptions-related symbols in fastcomp.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.12.0...1.12.1

v1.12.0: 2/22/2014

  • Improved the runtime abort error message when calling an invalid function pointer if compiled with -s ASSERTIONS=1 and 2. This allows the developer to better deduce errors with bad function pointers or function pointers casted and invoked via a wrong signature.
  • Added a new api function emscripten_set_main_loop_arg, which allows passing a userData pointer that will be carried via the function call, useful for object-oriented encapsulation purposes (#2114).
  • Fixed CMake MinSizeRel configuration type to actually optimize for minimal size with -Os.
  • Added support for GLES2 VAO extension OES_vertex_array_object for browsers that support it.
  • Fix issues with emscripten/html5.f when compiled with the SAFE_HEAP option.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.11.1...1.12.0

v1.11.1: 2/19/2014

  • Improved eglSwapBuffers to be spec-conformant.
  • Fixed an issue with asm.js validation and va_args (#2120).
  • Fixed asm.js validation issues found with fuzzing.
  • Added new link-time compiler flag -s RETAIN_COMPILER_SETTINGS=1, which enables a runtime API for querying which Emscripten settings were used to compile the file.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.11.0...1.11.1

v1.11.0: 2/14/2014

  • Implemented some new SDL library functions.
  • Renamed standard file descriptors to have handles 0, 1 and 2 rather than 1, 2 and 3 to coincide with unix numbering.
  • Improved embind support with smart pointers and mixins.
  • Improved the registerization -O3 optimization pass around switch-case constructs.
  • Upper-case files with suffix .C are now also recognized (#2109).
  • Fixed an issue with glGetTexParameter (#2112).
  • Improved exceptions support in fastcomp.
  • Added new linker option -s NO_EXIT_RUNTIME=1, which can be used to set a default value for the Module["noExitRuntime"] parameter at compile-time.
  • Improved SDL audio buffer queueing when the sample rate matches the native web audio graph sample rate.
  • Added an optimization that removes redundant Math.frounds in -O3.
  • Improved the default shell.html file.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.10.4...1.11.0

v1.10.4: 2/10/2014

v1.10.3: 2/9/2014

v1.10.2: 2/7/2014

  • Added basic FS unmount support.
  • Improved screen orientation lock API to return a success code.
  • Added PRECISE_F32 support to fastcomp.
  • Fixed issues in fastcomp related to special floating point literal serialization.
  • Improved SDL audio buffer queueing.
  • Added new link-time option -s WARN_UNALIGNED=1 to fastcomp to report compiler warnings about generated unaligned memory accesses, which can hurt performance.
  • Optimized libc strcmp and memcmp with the implementations from musl libc.
  • Optimized libc memcpy and memset to back to native code for large buffer sizes.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.10.1...1.10.2

v1.10.1: 1/31/2014

v1.10.0: 1/29/2014

  • Improved C++ exception handling.
  • Improved OpenAL library support.
  • Fixed an issue where loading side modules could try to allocate from sealed heap (#2060).
  • Fixed safe heap issues (2068).
  • Added new EM_ASM variants that return a value but do not receive any inputs (#2070).
  • Add support for simultaneously using setjmp and C++ exceptions in fastcomp.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.9.5...1.10.0

v1.9.5: 1/25/2014

v1.9.4: 1/24/2014

  • Add support for Ninja and Eclipse+Ninja builds with Emscripten+CMake.
  • Fixed regressions with GL emulation.
  • Added support for #if !X in .js library preprocessor.
  • Make the syntax EM_ASM("code"); not silently fail. Note that the proper form is EM_ASM(code); without double-quotes.
  • Optimize generated code size by minifying loop labels as well.
  • Revised the -O3 optimization level to mean "safe, but very slow optimizations on top of -O2", instead of the old meaning "unsafe optimizations". Using -O3 will now only do safe optimizations, but can be very slow compared to -O2.
  • Implemented a new registerization optimization pass that does extra variable elimination in -O3 and later to reduce the number of local variables in functions.
  • Implemented a new emscripten/html5.h interface that exposes common HTML5 APIs directly to C code without having to handwrite JS wrappers.
  • Improved error messages reported on user-written .js libraries containing syntax errors (#2033).
  • Fixed glBufferData() function call signature with null data pointer.
  • Added new option Module['filePackagePrefixURL'] that allows customizing the URL where the VFS package is loaded from.
  • Implemented glGetTexEnviv and glGetTexEnvfv in GL emulation mode.
  • Optimized the size of large memory initializer sections.
  • Fixed issues with the safe heap compilation option.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.9.3...1.9.4

v1.9.3: 1/17/2014

v1.9.2: 1/16/2014

v1.9.1: 1/16/2014

v1.9.0: 1/16/2014

v1.8.14: 1/15/2014

v1.8.13: 1/15/2014

v1.8.12: 1/15/2014

v1.8.11: 1/15/2014

v1.8.10: 1/14/2014

v1.8.9: 1/14/2014

v1.8.8: 1/14/2014

v1.8.7: 1/13/2014

  • Added support to numpad keycodes in glut support library.
  • Fix SIMD support with fastcomp.
  • Fixed a compiler error 'ran out of names' that could occur with too many minified symbol names.
  • Work around webkit imul bug https://bugs.webkit.org/show_bug.cgi?id=126345 (#1991)
  • Optimized desktop GL fixed function pipeline emulation path for better performance.
  • Added support for exceptions when building with fastcomp.
  • Fix and issue where the run() function could be called multiple times at startup (#1992)
  • Removed a relooper limitation with fixed buffer size.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.8.6...1.8.7

v1.8.6: 1/8/2014

  • Added support for the libuuid library, see http://linux.die.net/man/3/libuuid.
  • Fixed .js file preprocessor to preprocess recursively (#1984).
  • Fixed a compiler codegen issue related to overflow arithmetic (#1975)
  • Added new link-time optimization flag -s AGGRESSIVE_VARIABLE_ELIMINATION=1 that enables the aggressiveVariableElimination js optimizer pass, which tries to remove temporary variables in generated JS code at the expense of code size.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.8.5...1.8.6

v1.8.5: 1/7/2014

v1.8.4: 1/6/2014

v1.8.3: 1/5/2014

v1.8.2: 1/4/2014

v1.8.1: 1/3/2014

  • Added support for WebGL hardware instancing extension.
  • Improved fastcomp native LLVM backend support.
  • Added support for #include filename.js to JS libraries.
  • Deprecated --compression emcc command line parameter that manually compressed output JS files, due to performance issues. Instead, it is best to rely on the web server to serve compressed JS files.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.8.0...1.8.1

v1.8.0: 12/28/2013

v1.7.9: 12/27/2013

  • Added new command line parameter --em-config that allows specifying a custom location for the .emscripten configuration file.
  • Reintroduced relaxed asm.js heap sizes, which no longer need to be power of 2, but a multiple of 16MB is sufficient.
  • Added emrun command line tool that allows launching .html pages from command line on desktop and Android as if they were native applications. See https://groups.google.com/forum/#!topic/emscripten-discuss/t2juu3q1H8E . Adds --emrun compiler link flag.
  • Began initial work on the "fastcomp" compiler toolchain, a rewrite of the previous JS LLVM AST parsing and codegen via a native LLVM backend.
  • Added --exclude-file command line flag to emcc and a matching --exclude command line flag to file packager, which allows specifying files and directories that should be excluded while packaging a VFS data blob.
  • Improved GLES2 and EGL support libraries to be more spec-conformant.
  • Optimized legacy GL emulation code path. Added new GL_FFP_ONLY optimization path to fixed function pipeline emulation.
  • Added new core functions emscripten_log() and emscripten_get_callstack() that allow printing out log messages with demangled and source-mapped callstack information.
  • Improved BSD Sockets support. Implemented getprotobyname() for BSD Sockets library.
  • Fixed issues with simd support.
  • Various bugfixes: #1573, #1846, #1886, #1908, #1918, #1930, #1931, #1942, #1948, ..
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.7.8...1.7.9

v1.7.8: 11/19/2013

v1.7.7: 11/16/2013

v1.7.6: 11/15/2013

  • Added regex implementation from musl libc.
  • The command line parameter -s DEAD_FUNCTIONS=[] can now be used to explicitly kill functions coming from built-in library_xx.js.
  • Improved EGL support and GLES2 spec conformance.
  • Reverted -s TOTAL_MEMORY=x to require pow2 values, instead of the relaxed 'multiples of 16MB'. This is because the relaxed rule is released only in Firefox 26 which is currently in Beta and ships on the week of December 10th (currently in Beta). As of writing, current stable Firefox 25 does not yet support these.
  • Adjusted the default linker behavior to warn about all missing symbols, instead of silently ignoring them. Use -s WARN_ON_UNDEFINED_SYMBOLS=0 to suppress these warnings if necessary.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.7.5...1.7.6

v1.7.5: 11/13/2013

v1.7.4: 11/12/2013

v1.7.3: 11/12/2013

v1.7.2: 11/9/2013

  • The compiler now always generates a .js file that contains the generated source code even when compiling to a .html file.
  • Implemented depth+stencil buffer choosing behavior in GLUT, SDL and GLFW.
  • Fixed memory leaks generated by glGetString and eglGetString.
  • Greatly optimized startup times when virtual filesystems with a large amount of files in them.
  • Added some support for SIMD generated by LLVM.
  • Fixed some mappings with SDL keyboard codes.
  • Added a new command line parameter --no-heap-copy to compiler and file packager that can be used to optimize VFS memory usage at startup.
  • Updated libcxx to revision 194185, 2013-11-07.
  • Improvements to various library support.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.7.1...1.7.2

v1.7.1: 10/24/2013

v1.7.0: 10/23/2013

  • Adds mouse wheel events support in GLUT library.
  • Adds support for a new link parameter -s CASE_INSENSITIVE_VFS=1 to enable Emscripten virtual filesystem to search files ignoring case.
  • Numerous optimizations in both compilation and runtime stages.
  • Remove unnecessary whitespace, compact postSets function, and other optimizations in compilation output to save on generated file size.
  • Fixes float parsing from negative zero.
  • Removes the -s EMIT_GENERATED_FUNCTIONS link parameter as unneeded.
  • Fixes an issue where updating subranges of GL uniform arrays was not possible.
  • asm.js heap size (-s TOTAL_MEMORY=x) no longer needs to be a power of 2. As a relaxed rule, choosing any multiple of 16MB is now possible.
  • O1 optimization no longer runs the 'simplifyExpressions' optimization pass. This is to improve build iteration times when using -O1. Use -O2 to run that pass.
  • EM_ASM() can now be used even when compiling to asm.js.
  • All currently specified non-debugging-related WebGL 1 extensions are now enabled by default on startup, no need to ctx.getExtension() manually to enable them.
  • Improve readability of uncaught JavaScript exceptions that are thrown all the way up to the web console by printing out the stack trace of where the throw occurred.
  • Fix an issue when renaming a directory to a subdirectory.
  • Several compiler stability fixes.
  • Adds a JavaScript implementation of cxa_demangle function for demangling call stack traces at runtime for easier debugging.
  • GL context MSAA antialising is now DISABLED by default, to make the GL behavior consistent with desktop usage.
  • Added support to SDL, GLUT and GLFW libraries to specify MSAA on/off at startup.
  • Implemented glColor4ubv in GL emulation mode.
  • Fix an issue with LLVM keyword attribute ((constructor)) (#1155).
  • Fix an issue with va_args and -s UNALIGNED_MEMORY=1 (#1705).
  • Add initial support code for LLVM SIMD constructs and a JavaScript SIMD polyfill implementation from https://github.com/johnmccutchan/ecmascript_simd/ .
  • Fixed support for node.js native filesystem API NODEFS on Windows.
  • Optimize application startup times of Emscripten-compiled programs by enabling the virtual filesystem XHR and asm.js compilation to proceed in parallel when opening a page.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.6.4...1.7.0

v1.6.4: 9/30/2013

  • Implements a new preprocessor tool for preparsing C struct definitions (#1554), useful for Emscripten support library implementors.
  • Fix parsing issue with sscanf (#1668).
  • Improved the responsiveness of compiler print output on Windows.
  • Improved compilation times at link stage.
  • Added support for new "NODEFS" filesystem that directly accesses files on the native filesystem. Only usable with node.js when compiling to JS.
  • Added support for new IDBFS filesystem for accessing files in IndexedDB storage (#1601.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.6.3...1.6.4

v1.6.3: 9/26/2013

  • Emscripten CMake toolchain now generates archive files with .a suffix when project target type is static library, instead of generatic .bc files (#1648).
  • Adds iconv library from the musl project to implement wide functions in C library (#1670).
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.6.2...1.6.3

v1.6.2: 9/25/2013

  • Added support for dprintf() function (#1250).
  • Fixes several compiler stability issues (#1637, #1166, #1661, #1651 and more).
  • Enables support for WEBGL_depth_texture.
  • Adds support for new link flag -s GL_ASSERTIONS=1 which can be used to add extra validation layer to the Emscripten GL library to catch code issues.
  • Adds support to Web Audio API in SDL audio backend so that SDL audio now works in Chrome and new Opera as well.
  • Fixes an alpha blending issue with SDL_SetAlpha.
  • Implemented locale-related code in C library.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.6.1...1.6.2

v1.6.1: 9/22/2013

v1.6.0: 9/21/2013

  • Enable support for %[] pattern in scanf.
  • Added dependency tracking support to linked .js files in CMake toolchain.
  • The hex prefix 0x is now properly handled in sscanf (#1632).
  • Simplify internal compiler operations by removing the internal framework.js.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.5.9...1.6.0

v1.5.9: 9/15/2013

v1.5.8: 9/14/2013

v1.5.7: 8/30/2013

  • The script tag in default shell.html is now marked 'async', which enables loading the JS script code asynchronously in Firefox without making the main thread unresponsive.
  • Implemented new utility function emscripten_get_canvas_size() which returns the current Module element size in pixels.
  • Optimize code size in compiled side modules.
  • Optimize startup memory usage by avoiding unnecessary copying of VFS data at startup.
  • Add support for SDL_WM_ToggleFullScreen().
  • Add support for emscripten_get_now() when running in SpiderMonkey shell.
  • Added new environment variable EM_BUILD_VERBOSE=0,1,2,3 to set an extra compiler output verbosity level for debugging.
  • Added better support for dlopen() to simulate dynamic library loading in JavaScript.
  • Improved support for BSD sockets and networking.
  • Added new SOCKFS filesystem, which reads files via a network connection.
  • Avoid issues with long command line limitations in CMake toolchain by using response files.
  • Fix issues with client-side vertex data rendering in GL emulation mode.
  • Improved precision of clock_gettime().
  • Improve function outlining support.
  • Added support for using NMake generator with CMake toolchain.
  • Improved support for flexible arrays in structs (#1602).
  • Added ability to marshal UTF16 and UTF32 strings between C++ <-> JS code.
  • Added a new commandline tool validate_asms.py to help automating asm.js validation testing.
  • Improved stability with inline asm() syntax.
  • Updated libc headers to new version.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.5.6...1.5.7

v1.5.6: 8/17/2013

  • Improved BSD sockets support.
  • Added touch events support to GLUT library.
  • Added new --js-opts=0/1 command line option to control whether JS optimizer is run or not.
  • Improved OpenAL support.
  • Added new command line tool tools/find_bigvars.py which can be used on an output file to detect large functions and needs for outlining.
  • Merged link flags -s FORCE_GL_EMULATION and -s DISABLE_GL_EMULATION to a single opt-in flag -s LEGACY_GL_EMULATION=0/1 to control whether GL emulation is active.
  • Improved SDL input support.
  • Several stability-related compiler fixes.
  • Fixed source mapping generation support on Windows.
  • Added back the EMSCRIPTEN_KEEPALIVE attribute qualifier to help prevent inlining and to retain symbols in output without dead code elimination occurring.
  • Fix issues when marshalling UTF8 strings between C<->JS.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.5.5...1.5.6

v1.5.5: 8/9/2013

v1.5.4: 8/9/2013

  • Fixed multiple issues with C stdlib support.
  • Fix audio buffer queueing issues with OpenAL.
  • Improved BSD sockets support.
  • Added a new compile+link time command line option -Wno-warn-absolute-paths to hide the emscripten compiler warning when absolute paths are passed into the compiler.
  • Added new link flag -s STB_IMAGE=0/1 and integrate it to SDL image loading to enable synchronous image loading support with SDL.
  • Several improvements on function outlining support.
  • Fix issues with GLES2 interop support.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.5.3...1.5.4

v1.5.3: 6/28/2013

v1.5.2: 6/27/2013

  • Added support for generating source maps along the built application when -g is specified. This lets the browser show original .cpp sources when debugging.
  • GLUT and SDL improvements.
  • Added new link option -g where level=0-4, which allows controlling various levels of debuggability added to the output.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.5.1...1.5.2

v1.5.1: 6/22/2013

v1.5.0: 6/17/2013

v1.4.9: 6/8/2013

v1.4.8: 6/6/2013

v1.4.7: 6/2/2013

v1.4.6: 6/2/2013

v1.4.5: 6/1/2013

v1.4.4: 6/1/2013

  • Add support for symlinks in source files.
  • Fix various issues with SDL.
  • Added -s FORCE_ALIGNED_MEMORY=0/1 link time flag to control whether all loads and stores are assumed to be aligned.
  • Fix file packager to work with closure.
  • Major improvements to embind support, and optimizations.
  • Improve GL emulation.
  • Optimize VFS usage.
  • Allow emscripten to compile .m and .mm files.
  • Added new syntax --preload-file src@dst to file packager command line to allow placing source files to custom destinations in the FS.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.4.3...1.4.4

v1.4.3: 5/8/2013

v1.4.2: 5/3/2013

v1.4.1: 4/28/2013

v1.3.8: 4/29/2013

  • Improved 64-bit integer ops codegen.
  • Added Indexed DB support to vfs.
  • Improve warning message on dangerous function pointer casts when compiling in asm.js mode.
  • Added --use-preload-cache command line option to emcc, to be used with the file packager.
  • Fixes to libcextra.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.3.7...1.3.8

v1.3.7: 4/24/2013

  • Merge IMVU implementation of embind to emscripten trunk. Embind allows high-level C++ <-> JS types interop.
  • Enable asm.js compilation in -O1 and higher by default. Fix issues when compiling to asm.js.
  • Improve libc support with Emscripten with the musl libc headers.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.3.6...1.3.7

v1.3.6: 4/2/2013

v1.3.5: 3/25/2013

v1.3.4: 3/24/2013

v1.3.3: 3/23/2013

v1.3.2: 3/22/2013

v1.3.1: 3/19/2013

  • Improve SDL audio and mixer support.
  • Add GLES2 emulation features when -s FULL_ES2=1 is specified.
  • Add support for OpenAL.
  • Add new -s OPENAL_DEBUG=0/1 link command line option.
  • Fixed an issue with mouse coordinate being offset with canvas.
  • Removed -s UTF_STRING_SUPPORT=0 parameter, this is now always on.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.3.0...1.3.1

v1.3.0: 3/11/2013

v1.2.9: 3/7/2013

v1.2.8: 3/6/2013

v1.2.7: 3/6/2013

v1.2.6: 3/5/2013

v1.2.5: 3/5/2013

  • Greatly improve GL emulation support.
  • Handle %c in sscanf.
  • Improve compilation times by optimizing parallel execution in the linker.
  • Improve several compiler stability issues detected from fuzzing tests.
  • Implemented emscripten_jcache_printf.
  • Allow running emscripten.py outside emcc itself.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.2.4...1.2.5

v1.2.4: 2/2/2013

v1.2.3: 1/9/2013

v1.2.2: 1/8/2013

v1.2.1: 1/8/2013

v1.2.0: 1/1/2013

v1.1.0: 12/12/2012

  • Fix several issues with Windows support.
  • Added a standalone toolchain for CMake.
  • Added emscripten_run_script_string().
  • Optimize compilation times via threading.
  • Update to requiring Clang 3.2. Older versions may no longer work.
  • Several improvements to emscripten library support headers.
  • Full list of changes: https://github.com/emscripten-core/emscripten/compare/1.0.1a...1.1.0

v1.0.1a: 11/11/2012

v1.0.1: 11/11/2012

  • First commit that introduced versioning to the Emscripten compiler.