CMAKE Template

This project serves as an example of how to setup a cmake project in what is hopefully a straight forward way, vs some of the other cmake examples that are out there. cmake has so many options and can be difficult to debug it is easy to create a lot of bloat.

About me: I am not a cmake fan boy. Build systems can be very complicated and can leave developers spending way more time trying to compile than actually doing good things. I use make and cmake regularly, and depending on the project I will pick the solution that makes what I am trying to do easy.

Project Structure

.
├── benchmarks
│   ├── cmake_bench.cc
│   └── CMakeLists.txt
├── cmake
│   └── CPM.cmake
├── CMakeLists.txt
├── inc
│   └── cmk
│       └── cmake_proj.h
├── lib
│   ├── CMakeLists.txt
│   └── cmake_proj.cc
├── README.md
├── src
│   ├── CMakeLists.txt
│   └── cmake_src.cc
├── tests
│   ├── CMakeLists.txt
│   └── cmake_test.cc
└── third-party
    ├── benchmark-1.7.1.tar.gz
    ├── CMakeLists.txt
    ├── CMakeLists.txt.in
    ├── fftw-3.3.10.tar.gz
    └── googletest-1.13.0.tar.gz

Carrying your dependencies with you in your project

In some situations you may not have direct internet access, or in places where internet access is heavily restricted. For these situations it is better to bring your dependencies with you. I show how to carry those dependencies and build them using CPM for cmake projects and ExternalProject_Add for other projects, like fftw.

Building during configure time:

There are cases that sometimes arise where you may not want to use the system level version of a library. In these cases you may consider wanting to build your own version. I have ran across this numerous times with fftw. So rather than trying to build and install one on the host, I show how you can build it during configure time, and then you can link to it when you call target_link_libraries for you executable by adding PkgConfig::fftw3

The hack a coworker showed me was to basically create a separate cmake project third-party/CMakeLists.txt.in that is built during configuration time.

Benchmarks / Tests

I include googletest and google benchmark so you can easily test and benchmark your software. These are also packaged internally as tar.gz files.

make test

or

ctest

will execute the tests, you can also add github runners to force running the tests on each commit or PR to master.

Code Examples

I show how to build a basic library and link against it with a src file. The code is really dumb, and provides no real utility other than to provide the user with an example of how they might go about building their own libraries.

Building

It is setup to prefer to use clang vs gcc. You can omit the lines in the cmake_template/CMakeLists.txt by commenting them out or removing them.

find_program(CMAKE_C_COMPILER   NAMES $ENV{CC}  clang   gcc PATHS ENV PATH NO_DEFAULT_PATH)
find_program(CMAKE_CXX_COMPILER NAMES $ENV{CXX} clang++ g++ PATHS ENV PATH NO_DEFAULT_PATH)

Ninja

mkdir build
cd build
cmake .. -GNinja
ninja

Make

mkdir build
cd build
cmake ..
make -j`${nproc}`