Locates the first occurrence of a specified wide character in an
    array of wide characters.
    Format
      #include  <wchar.h>
      wchar_t wmemchr  (const wchar_t *s, wchar_t c, size_t n);
1 – Function Variants
    The wmemchr function has variants named _wmemchr32 and _wmemchr64
    for use with 32-bit and 64-bit pointer sizes, respectively.
2 – Arguments
 s
    A pointer to an array of wide characters to be searched.
 c
    The wide character value to search for.
 n
    The maximum number of wide characters in the array to be
    searched.
3 – Description
    The wmemchr function locates the first occurrence of the
    specified wide character in the initial n wide characters of
    the array pointed to by s.
4 – Return Values
    x                  A pointer to the first occurrence of the wide
                       character in the array.
    NULL               The specified wide character does not occur in
                       the array.