Re: [Mingw-users] Upstream GCC and __STRICT_ANSI__

[Greg C. <gch...@sb...>]

On 2009-06-05 15:37Z, John E. / TDM wrote:
> In recent upstream versions of GCC, enforcing strict C++98 or C++0x 
> standard-compliance and then including some of GCC's own standard 
> library headers causes errors like "::swprintf has not been declared" 
> and "::vswprintf has not been declared". This arises from the fact that 
> their declarations in mingwrt's stdio.h are surrounded by "#ifndef 
> __STRICT_ANSI__/#endif", but standard header <cwchar> references them 
> without such guards and other headers such as <iostream> include <cwchar>.
> 
> Why are these functions elided when operating in strict 
> standards-compliance mode (if it is in fact correct to do so)?

I would guess that the headers were written with C89 in mind,
as described here:
  http://www.mail-archive.com/deb...@li.../msg385630.html
OTOH, I don't have a copy of the C89 standard, so I can't say
for sure whether it had these functions--this might just be a
longstanding error. Otherwise...

> What is 
> the correct fix for this bug?

We could test the value of __STDC_VERSION__ in conjunction with
__STRICT_ANSI__, as newlib did here:
  http://sourceware.org/ml/newlib/2007/msg00800.html

Equivalently, to avoid a profusion of verbose and similar
conditionals like this:
  #if !defined(__STRICT_ANSI__) || defined(__cplusplus) || __STDC_VERSION__ >= 199901L
we could define a macro (in '_mingw.h') like __STRICT_C99__
as suggested here:
  http://www.mail-archive.com/gcc...@gc.../msg175049.html