Re: [libstdc++] numeric_limits.cc check the wchar_t limits facility

[Peter Schmid <schmid at snake dot iap dot physik dot tu-darmstadt dot de>]

On Fri, 26 Oct 2001, Benjamin Kosnik wrote:

|whatever happened to just using

|numeric_limits<wchar_t>::is_signed()

|?

Maybe my first statement was misleading. I would like to check if the
value of the is_signed member of the numeric_limits<wchar_t> class is
correct. The problem is that I need a way to get at the signedness
of the wchar_t type in a different way to make a comparison. The value of
the is_signed member is manually set in os_defines.h for a specific
operating system if there is a deviation from the default of
signedness. 

But there is no #define from the operationg system
like __CHAR_UNSIGNED__ for the signedness of the char type I
could employ to get at the signedness of the wchar_t type, I know of.

Additionally, according to the file os_defines.h for aix:
#if !defined(_AIX51) || !defined(__64BIT__)
#define __glibcpp_wchar_t_bits 16
#define __glibcpp_wchar_t_is_signed false
#endif

the signedness differs for different releases of the aix operating
system. Therefore, the appended code fragment could roughly work.


Hope this helps,

Peter Schmid

#ifdef __CHAR_UNSIGNED__
#define char_is_signed false
#else
#define char_is_signed true
#endif

void test_sign()
{
  VERIFY( std::numeric_limits<char>::is_signed == char_is_signed );

//new
#if defined(aix) || defined(hpux)
VERIFY( std::numeric_limits<wchar_t>::is_signed == false);
#else
VERIFY( std::numeric_limits<wchar_t>::is_signed == true);
#endif
#endif

}