strstr(3) — Linux manual page

strstr(3)               Library Functions Manual               strstr(3)

NAME         top

       strstr, strcasestr - locate a substring

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #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         top

       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         top

       These functions return a pointer to the beginning of the located
       substring, or NULL if the substring is not found.

       If needle is the empty string, the return value is always
       haystack itself.

ATTRIBUTES         top

       For an explanation of the terms used in this section, see
       attributes(7).
       ┌──────────────────────────────┬───────────────┬────────────────┐
       │ Interface                    │ Attribute     │ Value          │
       ├──────────────────────────────┼───────────────┼────────────────┤
       │ strstr()                     │ Thread safety │ MT-Safe        │
       ├──────────────────────────────┼───────────────┼────────────────┤
       │ strcasestr()                 │ Thread safety │ MT-Safe locale │
       └──────────────────────────────┴───────────────┴────────────────┘

STANDARDS         top

       strstr()
              C11, POSIX.1-2008.

       strcasestr()
              GNU.

HISTORY         top

       strstr()
              POSIX.1-2001, C89.

       strcasestr()
              GNU.

SEE ALSO         top

       memchr(3), memmem(3), strcasecmp(3), strchr(3), string(3),
       strpbrk(3), strsep(3), strspn(3), strtok(3), wcsstr(3)

COLOPHON         top

       This page is part of the man-pages (Linux kernel and C library
       user-space interface documentation) project.  Information about
       the project can be found at 
       ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report
       for this manual page, see
       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
       This page was obtained from the tarball man-pages-6.9.1.tar.gz
       fetched from
       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
       2024-06-26.  If you discover any rendering problems in this HTML
       version of the page, or you believe there is a better or more up-
       to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not
       part of the original manual page), send a mail to
       [email protected]

Linux man-pages 6.9.1          2024-06-15                      strstr(3)

Pages that refer to this page: memchr(3),  memmem(3),  strchr(3),  string(3),  strpbrk(3),  strsep(3),  strspn(3),  strtok(3),  wcsstr(3),  signal-safety(7)

HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH.