C in a Nutshell

Name

iswalnum

Synopsis

Ascertains whether a given wide character is alphanumeric

#include <wctype.h>
intiswalnum( wint_t wc );

The iswalnum() function is the wide-character version of the isalnum() character classification function. It tests whether its character argument is alphanumeric; that is, whether the character is either a letter of the alphabet or a digit. If the character is alphanumeric, iswalnum() returns a nonzero value (that is, true); if not, the function returns 0 (false).

Which characters are considered alphabetic or numeric depends on the current locale setting for the localization category LC_CTYPE, which you can query or change using the setlocale() function. In general, iswalnum() is true for all characters for which either iswalpha() or iswdigit() is true.

Example

wint_t wc, i;
int j, dummy;

setlocale( LC_CTYPE, "" );

wprintf( L"\nThe current locale for the 'is ...' functions is '%s'.\n",
         setlocale( LC_CTYPE, NULL ) );
wprintf( L"These are the alphanumeric wide characters"
         " in this locale:\n\n" );

for ( wc = 0, i = 0; wc < 1024; wc++ )
  if (iswalnum( wc ) )
    {
      if ( i % 25 == 0 )
        {
          wprintf( L"... more ...\n" );
          dummy = getchar();           // Wait a moment before printing more
          wprintf( L"Wide character     Code\n" );
          wprintf( L"-----------------------\n" );
        }
      wprintf(   L"%5lc            %4lu\n", wc, wc );
      i++;
    }
wprintf( L"-----------------------\n" );
return 0;

Here are samples from the output of this code. Which characters can be displayed correctly on the screen depends on the font used: