[Python-Dev] #ifdef __cplusplus? (original) (raw)

Matthieu Brucher matthieu.brucher at gmail.com
Fri Jan 2 19:31:40 CET 2009

Hi,

2009/1/2 Alexander Belopolsky <alexander.belopolsky at gmail.com>:

First, by copying c++-sig, let me invite C++ experts to comment on this thread and the tracker issue:

http://mail.python.org/pipermail/python-dev/2009-January/084685.html http://bugs.python.org/issue4805 My patch highlights several issues: _1. (OP's issue.) Do we need #ifdef cplusplus wrappers in .c files?

It seems that it is a reminiscence of old compilers, perhaps not even supported anymore, thus it shouldn't be an issue anymore.

2. Should malloc() calls be prefixed with explicit type casts?

When I learnt C, I was always told to explicitely cast.

3. Should use of void* pointers be discouraged when typed pointers will work?

I think type checking is good in C.

4. Should exported symbols be always declared in headers or is it ok to just declare them as extern in .c files where they are used?

I agree with you, declaration should be put in headers, to prevent a signature change for instance. One place is always better than several places (you have to define them somewhere if you want to call them without a warning). If we don't do this, we are back to the Fortran 77 days. Besides, if those functions are not to be advertized, nothing prevents them for inclusion inside "private" headers that are not included my Python.h. This way, you can benefit from C checks, without the advertizement (letting them in C files does not prevent their use, putting them in headers prevents crashes). With Visual Studio, you can say which function you want to export in your library. This can be done with gcc as well, even if it is not the default behavior.

5. Should the use of C++ keywords such as "new" or "class" be discouraged?

As CPython will not be ported to C++, I don't see the point of not using "new" and "class" for variables names inside a function.

Matthieu

Information System Engineer, Ph.D. Website: http://matthieu-brucher.developpez.com/ Blogs: http://matt.eifelle.com and http://blog.developpez.com/?blog=92 LinkedIn: http://www.linkedin.com/in/matthieubrucher

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