From 7a5fe7e2839978f653761dcdad54f047612898eb Mon Sep 17 00:00:00 2001 From: Michael Hines Date: Mon, 16 Sep 2024 08:00:03 -0400 Subject: [PATCH] Comment about hocclass alignment suggested by chatgpt. --- src/nrnpython/nrnpy_hoc.cpp | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/src/nrnpython/nrnpy_hoc.cpp b/src/nrnpython/nrnpy_hoc.cpp index 9fba7e2e9b..b6eb51a9b9 100644 --- a/src/nrnpython/nrnpy_hoc.cpp +++ b/src/nrnpython/nrnpy_hoc.cpp @@ -3432,20 +3432,25 @@ extern "C" NRN_EXPORT PyObject* nrnpy_hoc() { // then get error // TypeError: tp_basicsize for type 'hoc.HocClass' (424) is // too small for base 'type' (920) - hocclass_spec.basicsize = PyType_Type.tp_basicsize + sizeof(Symbol*); - // printf("hocclass_spec.basicsize = %d\n", hocclass_spec.basicsize); +#if 1 + hocclass_spec.basicsize = PyType_Type.tp_basicsize + sizeof(Symbol*); // and what about alignment? + // recommended by chatgpt size_t alignment = alignof(Symbol*); size_t remainder = hocclass_spec.basicsize % alignment; if (remainder != 0) { hocclass_spec.basicsize += alignment - remainder; // printf("aligned hocclass_spec.basicsize = %d\n", hocclass_spec.basicsize); } +#else + // chatgpt agrees that the following suggestion + // https://github.com/neuronsimulator/nrn/pull/2862/files#r1749797713 + // is equivalent to the '#if 1' fragment above. However the above + // may "ensures portability and correctness across different architectures." + hocclass_spec.basicsize = PyType_Type.tp_basicsize + sizeof(hocclass) - sizeof(PyTypeObject); +#endif - // printf("sizeof(hocclass) = %zd\n", sizeof(hocclass)); - // printf("sizeof(PyType_Type) = %zd\n", sizeof(PyType_Type)); - // printf("PyType_Type.tp_basicsize = %zd\n", PyType_Type.tp_basicsize); PyObject* custom_hocclass = PyType_FromSpec(&hocclass_spec); if (custom_hocclass == NULL) { return NULL;