1STRSTR(3) Linux Programmer's Manual STRSTR(3)
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6 strstr, strcasestr - locate a substring
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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
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15 #include <string.h>
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17 char *strcasestr(const char *haystack, const char *needle);
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20 The strstr() function finds the first occurrence of the substring nee‐
21 dle in the string haystack. The terminating '\0' characters are not
22 compared.
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24 The strcasestr() function is like strstr(), but ignores the case of
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28 These functions return a pointer to the beginning of the substring, or
29 NULL if the substring is not found.
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32 The strstr() function conforms to C89 and C99. The strcasestr() func‐
33 tion is a non-standard extension.
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36 Early versions of Linux libc (like 4.5.26) would not allow an empty
37 needle argument for strstr(). Later versions (like 4.6.27) work cor‐
38 rectly, and return haystack when needle is empty.
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41 index(3), memchr(3), rindex(3), strcasecmp(3), strchr(3), strpbrk(3),
42 strsep(3), strspn(3), strtok(3), wcsstr(3), feature_test_macros(7)
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45 This page is part of release 3.22 of the Linux man-pages project. A
46 description of the project, and information about reporting bugs, can
47 be found at http://www.kernel.org/doc/man-pages/.
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51GNU 2005-04-05 STRSTR(3)