wcscspn

   Compares the characters in a wide-character string against a
   set of wide characters. The function returns the length of the
   initial substring that is comprised entirely of characters that
   are not in the set of wide characters.

   Format

     #include  <wchar.h>

     size_t wcscspn  (const wchar_t *wstr1, const wchar_t *wstr2);
 

Additional information available:

Arguments       Description     Return_Value    Example