memmem

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



NAME
       memmem - locate a substring

SYNOPSIS
       #define _GNU_SOURCE         /* See feature_test_macros(7) */
       #include <string.h>

       void *memmem(const void *haystack, size_t haystacklen,
                    const void *needle, size_t needlelen);

DESCRIPTION
       The memmem() function finds the start of the first occurrence of the
       substring needle of length needlelen in the memory area haystack of
       length haystacklen.

RETURN VALUE
       The memmem() function returns a pointer to the beginning of the
       substring, or NULL if the substring is not found.

ATTRIBUTES
       For an explanation of the terms used in this section, see attributes(7).

       ┌──────────┬───────────────┬─────────┐
       │Interface Attribute     Value   │
       ├──────────┼───────────────┼─────────┤
       │memmem()  │ Thread safety │ MT-Safe │
       └──────────┴───────────────┴─────────┘
CONFORMING TO
       This function is a GNU extension.

BUGS
       This function was broken in Linux libraries up to and including libc
       5.0.9; there the needle and haystack arguments were interchanged, and a
       pointer to the end of the first occurrence of needle was returned.

       Both old and new libc's have the bug that if needle is empty, haystack-1
       (instead of haystack) is returned.  And glibc 2.0 makes it worse,
       returning a pointer to the last byte of haystack.  This is fixed in glibc
       2.1.

SEE ALSO
       strstr(3)

COLOPHON
       This page is part of release 3.53 of the Linux man-pages project.  A
       description of the project, and information about reporting bugs, can be
       found at http://www.kernel.org/doc/man-pages/.



GNU                                2008-12-05                          MEMMEM(3)