strstr(3) - Linux manual page (original) (raw)

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)](../man7/attributes.7.html).
   ┌───────────────────────────────┬───────────────┬────────────────┐
   │ **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)](../man3/memchr.3.html), [memmem(3)](../man3/memmem.3.html), [strcasecmp(3)](../man3/strcasecmp.3.html), [strchr(3)](../man3/strchr.3.html), [string(3)](../man3/string.3.html),
   [strpbrk(3)](../man3/strpbrk.3.html), [strsep(3)](../man3/strsep.3.html), [strspn(3)](../man3/strspn.3.html), [strtok(3)](../man3/strtok.3.html), [wcsstr(3)](../man3/wcsstr.3.html)

COLOPHON top

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   man-pages@man7.org

Linux man-pages 6.10 2024-07-23 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)