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Date: Fri, 18 May 2007 11:36:51 +0200
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Subject: Re: _GLIBCXX_USE_C99 not working?
From: "Christian Franke" <Christian DOT Franke AT t-online DOT de>
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Václav Haisman wrote:
>> ...
>>    
> Look into the cstdlib header. You will find that llabs(long long) and
> abs(long long) are in the __gnu_cxx namespace there. It is because
long
> long is not C++ standard type.
>  

Yes - but abs() and llabs() is also included into std namespace a few
lines later.
The problem is that ::strtold() is also included, but does not exist in
Cygwin's stdlib.h:

cstdlib:
...
#include "stdlib.h"
...
#if _GLIBCXX_USE_C99

namespace __gnu_cxx
{
...
  inline long long
  llabs(long long __x) { return __x >= 0 ? __x : -__x; }
...
  using ::strtold;
}

namespace std
{
...
  using __gnu_cxx::llabs;
...
  using __gnu_cxx::strtold;
}
#endif



The llabs() in my testcase was only intended as a real-world (found
in ddrescue) usage example.

The problem occurs also if cstdlib is simply included, but not used:

#define _GLIBCXX_USE_C99 1
#include <cstdlib>

/usr/lib/gcc/i686-pc-cygwin/3.4.4/include/c++/cstdlib:181:
 error: `::strtold' has not been declared
/usr/lib/gcc/i686-pc-cygwin/3.4.4/include/c++/cstdlib:200:
 error: `__gnu_cxx::strtold' has not been declared


This can be fixed by adding some dummy declaration of strtold:

#define _GLIBCXX_USE_C99 1
void strtold();
#include <cstdlib>


Christian




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