Name
memmem — locate a substring
Synopsis
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.
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. 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.
SEE ALSO
strstr(3), feature_test_macros(7)
Copyright 1993 David Metcalfe (david@prism.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manual page may be incorrect or out-of-date.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 (faith@cs.unc.edu)
Interchanged `needle' and `haystack'; added history, aeb, 980113.
|