_GLIBCXX_USE_C99 not working?

Christian Franke Christian.Franke@t-online.de
Fri May 18 10:59:00 GMT 2007

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 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:

#include "stdlib.h"

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;

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>

 error: `::strtold' has not been declared
 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>


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