1STRSTR(3)                  Linux Programmer's Manual                 STRSTR(3)
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NAME

6       strstr, strcasestr - locate a substring
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SYNOPSIS

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

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

27       These functions return a pointer to the beginning of the  located  sub‐
28       string, or NULL if the substring is not found.
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ATTRIBUTES

31       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
32       tributes(7).
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34       ┌─────────────────────────────────────┬───────────────┬────────────────┐
35       │Interface                            │ Attribute     │ Value          │
36       ├─────────────────────────────────────┼───────────────┼────────────────┤
37       │strstr()                             │ Thread safety │ MT-Safe        │
38       ├─────────────────────────────────────┼───────────────┼────────────────┤
39       │strcasestr()                         │ Thread safety │ MT-Safe locale │
40       └─────────────────────────────────────┴───────────────┴────────────────┘
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CONFORMING TO

43       strstr(): POSIX.1-2001, POSIX.1-2008, C89, C99.
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45       The strcasestr() function is a nonstandard extension.
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SEE ALSO

48       index(3), memchr(3), memmem(3),  rindex(3),  strcasecmp(3),  strchr(3),
49       string(3), strpbrk(3), strsep(3), strspn(3), strtok(3), wcsstr(3)
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COLOPHON

52       This  page  is  part of release 5.12 of the Linux man-pages project.  A
53       description of the project, information about reporting bugs,  and  the
54       latest     version     of     this    page,    can    be    found    at
55       https://www.kernel.org/doc/man-pages/.
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59GNU                               2021-03-22                         STRSTR(3)
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