STRSTR
Section: Linux Programmer's Manual (3)
Updated: 2005-04-05
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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
needle in the string haystack.
The terminating aq\0aq 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()
function 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 correctly,
and return haystack when needle is empty.
SEE ALSO
index(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 3.22 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/.