v*printf functions not available with g++ -std=c++0x

Corinna Vinschen corinna-cygwin@cygwin.com
Thu Aug 18 14:34:00 GMT 2011

On Aug 17 11:04, Ryan Johnson wrote:
> Hi all,
> I'm using the experimental gcc-4.5 package and hit a strange error:
> c++0x mode suppresses the definition of the v*printf() family of
> functions in stdio.h in c++0x mode. The offending code seems to be:
> #if !defined(__STRICT_ANSI__) || (__STDC_VERSION__ >= 199901L)
> #ifndef _REENT_ONLY
> ...
> int     _EXFUN(vsnprintf, (char *, size_t, const char *, __VALIST)
>                _ATTRIBUTE ((__format__ (__printf__, 3, 0))));
> ...
> #endif
> #endif
> Running `g++ -std=c++0x -dM -E' indicates that __STRICT_ANSI__  is
> defined while _REENT_ONLY and __STDC_VERSION__ are not.
> Oddly, functions like _vsnprintf_r are still available for some
> strange reason (aren't they extensions?). I hope this is a bug
> rather than a requirement of the new standard; meanwhile, using
> std=gnu++0x works around the problem.

If I try that with Yaakov's 4.5.3 cross compilers, then __STRICT_ANSI__
is not defined with -std=c__0x, unless I also specify `-ansi' on the
command line.  However, there's a weird warning:

  $ i686-pc-cygwin-g++ -std=c++0x -dM -E - < /dev/null | grep ANSI
  cc1: warning: command line option "-std=c++0x" is valid for C++/ObjC++ but not for C

Well, sure, that's why I called g++, not gcc...


Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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