New submission from Mike Frysinger:
the ac_cv_have_long_long_format test has a nice compile-time fallback for gcc
based compilers:
CFLAGS="$CFLAGS -Werror -Wformat"
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
#include <stdio.h>
#include <stddef.h>
]], [[
char *buffer;
sprintf(buffer, "%lld", (long long)123);
sprintf(buffer, "%lld", (long long)-123);
sprintf(buffer, "%llu", (unsigned long long)123);
]])],
ac_cv_have_long_long_format=yes
)
unfortunately, this turns on the global -Werror flag in order to check things.
that means if the code triggers unrelated warnings, the test still fails ;(.
this comes up w/bionic which complains about unsafe use of the sprintf
function, and can come up in general in this code because buffer is not
initialized :).
the good news is that gcc-4.2 has supported a directed -Werror=format option.
https://gcc.gnu.org/onlinedocs/gcc-4.2.4/gcc/Warning-Options.html
so instead of using -Werror -Wformat, you could use -Werror=format. the
downside is that the fallback no longer works with <=gcc-4.1, but maybe that's
ok considering gcc-4.2 was released May 2007 (almost 9 years ago) ?
note: this also applies to various other tests in the configure file.
NB: landing a fix in py3.5+ (and ignoring 3.[0-4]) is fine, but please also to
fix py2.7 :)
----------
components: Cross-Build
messages: 252968
nosy: vapier
priority: normal
severity: normal
status: open
title: improve ac_cv_have_long_long_format GCC fallback
type: enhancement
versions: Python 2.7, Python 3.2, Python 3.3, Python 3.4, Python 3.5, Python 3.6
_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue25397>
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