On Thu, Feb 24, 2022 at 11:10 PM Barry <barry@barrys-emacs.org> wrote:
"Python 3.11 and newer versions use C11 without optional features. The public C API should be compatible with C++." https://github.com/python/peps/pull/2309/files
Should is often read as meaning optional when writing specs. Can you say “must be compatible with C++”.
I plan to attempt to write an actual test for that, rather than a vague sentence in a PEP. For now, "should" is a deliberate choice: I don't know exactly which C++ version should be targeted and if it's really an issue or not. For example, C++20 reserves the "module" keyword, whereas Python uses it in its C API. Example: PyAPI_FUNC(int) PyModule_AddType(PyObject *module, PyTypeObject *type); See: * https://bugs.python.org/issue39355 * https://github.com/pythoncapi/pythoncapi_compat/issues/21 -- I made a change in the datatable project to add Python 3.11 support using the pythoncapi_compat.h header file. Problem: this *C* header file produced new warnings in datatable extension module which with built with a C++ compiler: https://github.com/h2oai/datatable/pull/3231#issuecomment-1032864790 Examples: | src/core/lib/pythoncapi_compat.h:272:52: warning: zero as null pointer constant [-Wzero-as-null-pointer-constant] | || tstate->c_profilefunc != NULL); | ^~~~ | nullptr and | src/core/lib/pythoncapi_compat.h:170:12: warning: use of old-style cast [-Wold-style-cast] | return (PyCodeObject *)_Py_StealRef(PyFrame_GetCode(frame)); | ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ I made pythoncapi_compat.h compatible with C++ (fix C++ compiler warnings) by using nullptr and reinterpret_cast<TYPE>(EXPR) cast if the __cplusplus macro is defined, or NULL and ((TYPE)(EXPR)) cast otherwise. datatable also uses #include "Python.h". I don't know there were only C++ compiler warnings on "pythoncapi_compat.h". Maybe because datatable only uses static inline functions from "pythoncapi_compat.h", but it may also emit the same warnings if tomorrow some static inline functions of "Python.h" are used. For now, I prefer to put a reminder in PEP 7 that the "Python.h" C API is consumed by C++ projects. Victor -- Night gathers, and now my watch begins. It shall not end until my death.