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         /* See feature_test_macros(7) */

       #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 null
       bytes ('\0') 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),
       string(3), strpbrk(3), strsep(3), strspn(3), strtok(3),
       wcsstr(3)

COLOPHON

       This page is part of release 3.35 of the Linux man-pages
       project.  A description of the project, and information about
       reporting bugs, can be found at
       http://man7.org/linux/man-pages/.



GNU                                       2011-09-28                                STRSTR(3)