Author: Armin Rigo <ar...@tunes.org> Branch: Changeset: r2614:fca64086ec22 Date: 2016-01-19 16:22 +0100 http://bitbucket.org/cffi/cffi/changeset/fca64086ec22/
Log: clarify (thanks Rémi) diff --git a/doc/source/using.rst b/doc/source/using.rst --- a/doc/source/using.rst +++ b/doc/source/using.rst @@ -476,16 +476,20 @@ Python function object that is, at runtime, attached with ``@ffi.def_extern()``. -The ``@ffi.def_extern()`` decorator should be applied to a global -function, but *only once.* This is because each function from the cdef with -``extern "Python"`` turns into only one C function. To support some -corner cases, it is possible to redefine the attached Python function -by calling ``@ffi.def_extern()`` again---but this is not recommended! -Better write the single global Python function more flexibly in the -first place. Calling ``@ffi.def_extern()`` again changes the C logic -to call the new Python function; the old Python function is not -callable any more and the C function pointer you get from -``lib.my_function`` is always the same. +The ``@ffi.def_extern()`` decorator should be applied to **global +functions,** one for each ``extern "Python"`` function of the same +name. + +To support some corner cases, it is possible to redefine the attached +Python function by calling ``@ffi.def_extern()`` again for the same +name---but this is not recommended! Better attach a single global +Python function for this name, and write it more flexibly in the first +place. This is because each ``extern "Python"`` function turns into +only one C function. Calling ``@ffi.def_extern()`` again changes this +function's C logic to call the new Python function; the old Python +function is not callable any more. The C function pointer you get +from ``lib.my_function`` is always this C function's address, i.e. it +remains the same. Extern "Python" and ``void *`` arguments ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ _______________________________________________ pypy-commit mailing list pypy-commit@python.org https://mail.python.org/mailman/listinfo/pypy-commit
