strstr(3)

1strstr(3)                  Library Functions Manual                  strstr(3)
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NAME

6       strstr, strcasestr - locate a substring
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LIBRARY

9       Standard C library (libc, -lc)
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SYNOPSIS

12       #include <string.h>
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14       char *strstr(const char *haystack, const char *needle);
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16       #define _GNU_SOURCE         /* See feature_test_macros(7) */
17       #include <string.h>
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19       char *strcasestr(const char *haystack, const char *needle);
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DESCRIPTION

22       The  strstr() function finds the first occurrence of the substring nee‐
23       dle in the string haystack.  The terminating null bytes ('\0') are  not
24       compared.
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26       The  strcasestr()  function  is  like strstr(), but ignores the case of
27       both arguments.
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RETURN VALUE

30       These functions return a pointer to the beginning of the  located  sub‐
31       string, or NULL if the substring is not found.
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33       If  needle is the empty string, the return value is always haystack it‐
34       self.
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ATTRIBUTES

37       For an  explanation  of  the  terms  used  in  this  section,  see  at‐
38       tributes(7).
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40       ┌─────────────────────────────────────┬───────────────┬────────────────┐
41       │Interface                            │ Attribute     │ Value          │
42       ├─────────────────────────────────────┼───────────────┼────────────────┤
43       │strstr()                             │ Thread safety │ MT-Safe        │
44       ├─────────────────────────────────────┼───────────────┼────────────────┤
45       │strcasestr()                         │ Thread safety │ MT-Safe locale │
46       └─────────────────────────────────────┴───────────────┴────────────────┘
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STANDARDS

49       strstr()
50              C11, POSIX.1-2008.
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52       strcasestr()
53              GNU.
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HISTORY

56       strstr()
57              POSIX.1-2001, C89.
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59       strcasestr()
60              GNU.
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