memmem — locate a substring
#define _GNU_SOURCE #include <string.h>
void
*memmem( |
const void * | haystack, |
| size_t | haystacklen, | |
| const void * | needle, | |
| size_t | needlelen); |
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.
The memmem() function
returns a pointer to the beginning of the substring, or NULL
if the substring is not found.
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. Since libc 5.0.9 is still widely used, this is
a dangerous function to use.
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, and returns a pointer
to the last byte of haystack. This is fixed in
glibc 2.1.
This page is part of release 2.79 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/.
|
Copyright 1993 David Metcalfe (davidprism.demon.co.uk) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. References consulted: Linux libc source code 386BSD man pages Modified Sat Jul 24 18:50:48 1993 by Rik Faith (faithcs.unc.edu) Interchanged 'needle' and 'haystack'; added history, aeb, 980113. |