STRSTR Section: Linux Programmer's Manual (3) Updated: April 12, 2025 Index   NAME strstr - locate a substring   SYNOPSIS #include <string.h> char *strstr(const char *haystack, const char *needle);   DESCRIPTION The strstr() function finds the first occurrence of the substring needle in the string haystack. The terminating `\0' characters are not compared.   RETURN VALUE The strstr() function returns a pointer to the beginning of the substring, or NULL if the substring is not found.   BUGS Early versions of Linux libc (like 4.5.26) would not allow an empty argument. Later versions (like 4.6.27) work correctly, and return haystack when needle is empty.   SEE ALSO   Index NAME SYNOPSIS DESCRIPTION RETURN VALUE BUGS SEE ALSO This document was created by using the manual pages. Time: 11:58:06 GMT, March 24, 2025