char *strstr(const char *s1, const char *s2);
The strstr() function shall locate the first occurrence in the string pointed to by s1 of the sequence of bytes (excluding the terminating null byte) in the string pointed to by s2.
Upon successful completion, strstr() shall return a pointer to the located string or a null pointer if the string is not found.
If s2 points to a string with zero length, the function shall return s1.
No errors are defined.
The following sections are informative.
COPYRIGHTPortions 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 .