It should be exactly what hes looking for...
char *strstr( const char *string, const char *strCharSet );
Return Value
Each of these functions returns a pointer to the first occurrence of strCharSet in string, or NULL if strCharSet does not appear in string. If strCharSet points to a string of zero length, the function returns string.
Parameters
string
Null-terminated string to search
strCharSet
Null-terminated string to search for