1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
2 .\" and Copyright (c) 2008 Linux Foundation, written by Michael Kerrisk
3 .\" <mtk.manpages@gmail.com>
5 .\" Permission is granted to make and distribute verbatim copies of this
6 .\" manual provided the copyright notice and this permission notice are
7 .\" preserved on all copies.
9 .\" Permission is granted to copy and distribute modified versions of this
10 .\" manual under the conditions for verbatim copying, provided that the
11 .\" entire resulting derived work is distributed under the terms of a
12 .\" permission notice identical to this one.
14 .\" Since the Linux kernel and libraries are constantly changing, this
15 .\" manual page may be incorrect or out-of-date. The author(s) assume no
16 .\" responsibility for errors or omissions, or for damages resulting from
17 .\" the use of the information contained herein. The author(s) may not
18 .\" have taken the same level of care in the production of this manual,
19 .\" which is licensed free of charge, as they might when working
22 .\" Formatted or processed versions of this manual, if unaccompanied by
23 .\" the source, must acknowledge the copyright and authors of this work.
25 .\" Modified Mon Apr 12 12:49:57 1993, David Metcalfe
26 .\" Modified Sat Jul 24 18:56:22 1993, Rik Faith (faith@cs.unc.edu)
27 .\" Modified Wed Feb 20 21:09:36 2002, Ian Redfern (redferni@logica.com)
28 .\" 2008-07-09, mtk, add rawmemchr()
30 .TH MEMCHR 3 2012-04-23 "" "Linux Programmer's Manual"
32 memchr, memrchr, rawmemchr \- scan memory for a character
35 .B #include <string.h>
37 .BI "void *memchr(const void *" s ", int " c ", size_t " n );
39 .BI "void *memrchr(const void *" s ", int " c ", size_t " n );
41 .BI "void *rawmemchr(const void *" s ", int " c );
45 Feature Test Macro Requirements for glibc (see
46 .BR feature_test_macros (7)):
55 function scans the initial
60 for the first instance of
64 and the bytes of the memory area pointed to by
74 except that it searches backward from the end of the
78 instead of forward from the beginning.
82 function is similar to
84 it assumes (i.e., the programmer knows for certain)
87 lies somewhere in the memory area starting at the location pointed to by
89 and so performs an optimized search for
91 (i.e., no use of a count argument to limit the range of the search).
94 is not found, the results are unpredictable.
95 The following call is a fast means of locating a string's
96 terminating null byte:
100 char *p = rawmemchr(s,\ \(aq\\0\(aq);
108 functions return a pointer
109 to the matching byte or NULL if the character does not occur in
110 the given memory area.
114 function returns a pointer to the matching byte, if one is found.
115 If no matching byte is found, the result is unspecified.
118 first appeared in glibc in version 2.1.
121 first appeared in glibc in version 2.2.
125 function conforms to SVr4, 4.3BSD, C89, C99, POSIX.1-2001.
129 function is a GNU extension, available since glibc 2.1.91.
133 function is a GNU extension, available since glibc 2.1.