STRSTR(3) Linux Programmer's Manual STRSTR(3)NAME
strstr, strcasestr - locate a substring
SYNOPSIS
#include <string.h>
char *strstr(const char *haystack, const char *needle);
#define _GNU_SOURCE
#include <string.h>
char *strcasestr(const char *haystack, const char *needle);
DESCRIPTION
The strstr() function finds the first occurrence of the substring nee‐
dle in the string haystack. The terminating '\0' characters are not
compared.
The strcasestr() function is like strstr(), but ignores the case of
both arguments.
RETURN VALUE
These functions return a pointer to the beginning of the substring, or
NULL if the substring is not found.
CONFORMING TO
The strstr() function conforms to C89 and C99. The strcasestr() func‐
tion is a non-standard extension.
BUGS
Early versions of Linux libc (like 4.5.26) would not allow an empty
needle argument for strstr(). Later versions (like 4.6.27) work cor‐
rectly, and return haystack when needle is empty.
SEE ALSOindex(3), memchr(3), rindex(3), strcasecmp(3), strchr(3), strpbrk(3),
strsep(3), strspn(3), strtok(3), wcsstr(3), feature_test_macros(7)COLOPHON
This page is part of release 3.15 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
GNU 2005-04-05 STRSTR(3)
