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

6       memmem - locate a substring
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SYNOPSIS

9       #define _GNU_SOURCE
10       #include <string.h>
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12       void *memmem(const void *haystack, size_t haystacklen,
13                    const void *needle, size_t needlelen);
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DESCRIPTION

16       The  memmem()  function  finds the start of the first occurrence of the
17       substring needle of length needlelen in the  memory  area  haystack  of
18       length haystacklen.
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RETURN VALUE

21       The  memmem()  function  returns a pointer to the beginning of the sub‐
22       string, or NULL if the substring is not found.
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CONFORMING TO

25       This function is a GNU extension.
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BUGS

28       This function was broken in Linux libraries up to  and  including  libc
29       5.0.9; there the needle and haystack arguments were interchanged, and a
30       pointer to the end of the first occurrence of needle was returned.
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32       Both old and  new  libc's  have  the  bug  that  if  needle  is  empty,
33       haystack-1  (instead  of haystack) is returned.  And glibc 2.0 makes it
34       worse, returning a pointer to the last byte of haystack.  This is fixed
35       in glibc 2.1.
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SEE ALSO

38       strstr(3), feature_test_macros(7)
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COLOPHON

41       This  page  is  part of release 3.25 of the Linux man-pages project.  A
42       description of the project, and information about reporting  bugs,  can
43       be found at http://www.kernel.org/doc/man-pages/.
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47GNU                               2008-12-05                         MEMMEM(3)