[ python-Bugs-1337400 ] Python.h should include system headers properly [POSIX]

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Bugs item #1337400, was opened at 2005-10-25 14:38
Message generated for change (Comment added) made by papadopo
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Category: Python Interpreter Core
Group: Python 2.4
Status: Open
Resolution: None
Priority: 5
Submitted By: Dimitri Papadopoulos (papadopo)
Assigned to: Nobody/Anonymous (nobody)
Summary: Python.h should include system headers properly [POSIX]

Initial Comment:
In Python 2.4.2, Python.h looks like this:

	#include <limits.h>
	[...]
	#include <stdio.h>
	[...]
	#include <string.h>
	#include <errno.h>
	#include <stdlib.h>
	#ifdef HAVE_UNISTD_H
	#include <unistd.h>
	#endif

On POSIX platforms <unistd.h> should be included first!

Indeed it includes headers such as
<sys/feature_tests.h> on Solaris, <standards.h> on
Irix, or <features.h> on GNU systems, which define
macros that specify the system interfaces to use,
possibly depending on compiler options, which in turn
may enable/disable/modify parts of other system headers
such as <limits.h> or <errno.h>.

By including <unistd.h>, you ensure consistent systems
interfaces are specified in all system headers included
by Python sources.

This may seem rather academic, but it actually breaks
my Solaris builds: I need to compile Python using Sun's
C compiler when building Python for performance and
GNU's C++ compiler when building Python modules written
in C++ for compatibility with C++ libraries used by
these modules that can't be compiled with Sun's C++
compiler. So the same Python.h is used by Sun's C
compiler (which it was created for in the first place)
and GNU's C++ compiler. GNU's C++ compiler fails to
compile some modules. Unfortunately I can't recall the
exact modules and error messages right now, but
including <unistd.h> fixes the problem.


----------------------------------------------------------------------

>Comment By: Dimitri Papadopoulos (papadopo)
Date: 2005-10-25 15:57

Message:
Logged In: YES 
user_id=52414

Oops... Instead of
 including <unistd.h> fixes the problem.
please read
  including <unistd.h> first fixes the problem.

Here is an example to reproduce the problem:

$ cat > foo.cpp
#include <Python.h>
#include <cwchar>
$
$ g++ -I/usr/local/python/include/python2.4 -c foo.cpp
[...]
/usr/local/gcc-4.0.2/lib/gcc/sparc-sun-solaris2.8/4.0.2/../../../../include/c++/4.0.2/cwchar:145:
error: '::btowc' has not been declared
[...]
$
$ cat > foo.cpp
#include <unistd.h>
#include <Python.h>
#include <cwchar>
$
$ g++ -I/usr/local/python/include/python2.4 -c foo.cpp
[...]
$ 


----------------------------------------------------------------------

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