_GLIBCXX_USE_C99 not working?
Václav Haisman
v.haisman@sh.cvut.cz
Fri May 18 08:59:00 GMT 2007
Christian Franke wrote:
> Defining _GLIBCXX_USE_C99 does not work with current Cygwin C++ includes.
>
> Testcase:
>
> #define _GLIBCXX_USE_C99 1 // need std::llabs()
>
> #include <cstdlib>
>
> long long f(long long x)
> {
> return std::llabs(x);
> }
>
>
> Compile fails with:
>
> /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
>
>
> The function strtold() does actually not exist in stdlib.h
> and the corresponding _GLIBCXX_HAVE_STRTOLD in
> /usr/lib/gcc/i686-pc-cygwin/3.4.4/include/c++/i686-pc-cygwin/bits/c++config.h
>
> is not set.
>
> But "using ::strtold" exists in the "#if _GLIBCXX_USE_C99" part of
> /usr/lib/gcc/i686-pc-cygwin/3.4.4/include/c++/cstdlib
>
> Workaround: delete the two "using ::strtold" lines from cstdlib.
>
> Christian
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.
--
Vaclav Haisman
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