Date: Fri, 01 Feb 2013 15:31:19 +0200 From: Andriy Gapon <avg@FreeBSD.org> To: Dimitry Andric <dim@FreeBSD.org> Cc: toolchain@FreeBSD.org, freebsd-hackers <freebsd-hackers@FreeBSD.org> Subject: Re: base gcc and _GLIBCXX_USE_C99 Message-ID: <510BC3A7.5040405@FreeBSD.org> In-Reply-To: <510BBE48.4070101@FreeBSD.org> References: <5106953E.2020907@FreeBSD.org> <510BBCAD.3070705@FreeBSD.org> <510BBE48.4070101@FreeBSD.org>
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on 01/02/2013 15:08 Dimitry Andric said the following: > On 2013-02-01 14:01, Andriy Gapon wrote: >> on 28/01/2013 17:11 Andriy Gapon said the following: >>> I wonder why the following is the case for the base gcc. >>> /usr/include/c++/4.2/bits/c++config.h: >>> >>> /* Define if C99 functions or macros from <wchar.h>, <math.h>, <complex.h>, >>> <stdio.h>, and <stdlib.h> can be used or exposed. */ >>> /* #undef _GLIBCXX_USE_C99 */ >>> >>> Because of this undef there is no e.g. std::strtoll(). >>> Ditto for other things in stdlib.h. > > Maybe this support can't be enabled, because we don't expose all the > required functions yet? Or maybe it is just something that was > committed years ago, and then forgotten. > > If we are sure that all the C99 functions libstdc++ requires are now > available and working, I see no problem in turning on _GLIBCXX_USE_C99. Having looked into the source code of a recent GCC I get an impression that this is a silliness on GCC's part (plus incompleteness of FreeBSD C99 support, it seems). cstdlib would provide e.g. std::strtoull only when _GLIBCXX_USE_C99 is defined. Now looking at libstdc++-v3/acinclude.m4 we can see that there is a dedicated check "for ISO C99 support in <stdlib.h>". That check sets variable glibcxx_cv_c99_stdlib. But, _GLIBCXX_USE_C99 is set only if all of glibcxx_cv_c99_math, glibcxx_cv_c99_complex, glibcxx_cv_c99_stdio, glibcxx_cv_c99_stdlib and glibcxx_cv_c99_wchar are set. So if glibcxx_cv_c99_stdlib is yes, but something like glibcxx_cv_c99_complex is no, then no std::strtoull for me. Not sure why GCC couldn't have a dedicated macro "_GLIBCXX_USE_C99_STDLIB" like e.g. _GLIBCXX_USE_C99_MATH that it does have. -- Andriy Gapon
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