1.\" $OpenBSD: memchr.3,v 1.10 2011/07/25 00:38:52 schwarze Exp $ 2.\" 3.\" Copyright (c) 1990, 1991 The Regents of the University of California. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to Berkeley by 7.\" Chris Torek and the American National Standards Committee X3, 8.\" on Information Processing Systems. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 3. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.Dd $Mdocdate: July 25 2011 $ 35.Dt MEMCHR 3 36.Os 37.Sh NAME 38.Nm memchr 39.Nd locate byte in byte string 40.Sh SYNOPSIS 41.Fd #include <string.h> 42.Ft void * 43.Fn memchr "const void *b" "int c" "size_t len" 44.Ft void * 45.Fn memrchr "const void *b" "int c" "size_t len" 46.Sh DESCRIPTION 47The 48.Fn memchr 49function locates the first occurrence of 50.Fa c 51(converted to an 52.Li unsigned char ) 53in string 54.Fa b . 55.Pp 56The 57.Fn memrchr 58function behaves like 59.Fn memchr , 60except that it locates the last occurrence of 61.Fa c 62in string 63.Fa b . 64.Sh RETURN VALUES 65The 66.Fn memchr 67and 68.Fn memrchr 69functions return a pointer to the byte located, or 70.Dv NULL 71if no such byte exists within 72.Fa len 73bytes. 74.Sh SEE ALSO 75.Xr strchr 3 , 76.Xr strcspn 3 , 77.Xr strpbrk 3 , 78.Xr strrchr 3 , 79.Xr strsep 3 , 80.Xr strspn 3 , 81.Xr strstr 3 , 82.Xr strtok 3 , 83.Xr wmemchr 3 84.Sh STANDARDS 85The 86.Fn memchr 87function conforms to 88.St -ansiC . 89.Pp 90The 91.Fn memrchr 92function is an 93.Ox 94extension. 95.Sh HISTORY 96The 97.Fn memchr 98function first appeared in 99.At V 100and was reimplemented for 101.Bx 4.3 Tahoe . 102