Locates the first occurrence in the string pointed to by s1 of
    the sequence of wide characters in the string pointed to by s2.

    Format

      #include  <wchar.h>

      wchar_t *wcsstr  (const wchar_t *s1, const wchar_t *s2);

1 - Function Variants

    The wcsstr function has variants named _wcsstr32 and _wcsstr64
    for use with 32-bit and 64-bit pointer sizes, respectively.

2 - Arguments

 s1, s2

    Pointers to null-terminated, wide-character strings.

3 - Description

    If s2 points to a wide-character string of 0 length, the wcsstr
    function returns s1.

4 - Return Values

    x                  A pointer to the located string.
    NULL               Indicates an error; the string was not found.