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  sub-
       string is not found.

CONFORMING TO
       The strstr() function conforms to C89 and C99.  The strcasestr() function is a nonstandard
       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 3.53 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                                         2011-09-28                                  STRSTR(3)