The wcsstr() function shall locate the first occurrence in the
wide-character string pointed to by ws1 of the sequence of wide
characters (excluding the terminating null wide character) in the
wide-character string pointed to by ws2.
Upon successful completion, wcsstr() shall return a pointer to the
located wide-character string, or a null pointer if the wide-character string
is not found.
If ws2 points to a wide-character string with zero length, the function
shall return ws1.
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html