[Python-Dev] Good way of finding out what C functions we have? (original) (raw)

Brett C. bac at OCF.Berkeley.EDU
Mon Sep 29 22:07:58 EDT 2003

Martin v. Löwis wrote:

"Brett C." <bac at OCF.Berkeley.EDU> writes:

Does there happen to be a better way to find out what functions we check for beyond grepping configure.in? The entire reason I bothered to do so much research is I thought we were only supposed to assume ANSI C with POSIX (which, from what I can tell, strdup() is not). Actually, strdup is in POSIX: http://www.opengroup.org/onlinepubs/007904975/functions/strdup.html

Shows how much I know; I found that last night but since it didn't say POSIX anywhere I thought it was part of another standard. I guess the "Issue 5" mention means that BASE is POSIX? Or is IEEE 1003.1 basically POSIX?

If we still check for it, it is because it might not have been available on some system, at some point in time.

We don't only check for it, but we have a replacement implementation (the comment for Python/strdup.c seems to suggest it is needed by the parser).

Because of this I would like to list in the Python development guide I am writing up all of the places one can check for info; what configure.in checks for or handles and pyport.h come to mind. It would be nice to have a place that lists all the places one can check for C functionality that are not in the Python/C API directly. If people have other places in the code that one should check please let me know so I can make sure it makes it into the doc and prevents me from having to come up with another Brett Newbie Question. =) I would look in pyconfig.h.in as the first thing. There is a pitfall, though: presence of some HAVEfoo in pyconfig.h does not mean that Python gracefully deals with the absence of foo. When converting configure to autoconf 2.5x, I checked all macros to determine whether they were still in use, but some may have become unused/not processed correctly since. That would be a bug, of course.

What does happen if a HAVE_foo is actually required? Does the build fail or will configure halt and say that the build will fail if you proceed?

And if no one objects I will mention that looking in pyconfig.h.in is a good place to look to see what C functions that are non-POSIX and non-ANSI C we check for and pyport.h has helpful stuff as well.

-Brett

More information about the Python-Dev mailing list