wcslen - determine the length of a wide-character string
#include <wchar.h>
size_t wcslen (const wchar_t *s);
The wcslen function is the wide-character equivalent of
the strlen function. It determines the length of the wide-
character string pointed to by s, not including the termi
nating L'\0' character.
The wcslen function returns the number of wide characters
in s.
ISO/ANSI C, UNIX98
strlen(3)