1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" Chris Torek and the American National Standards Committee X3, 6.\" on Information Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.Dd April 9, 2008 33.Dt MEMCHR 3 34.Os 35.Sh NAME 36.Nm memchr 37.Nd locate byte in memory object 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In 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 50locates the first occurrence of 51.Fa c 52(converted to an 53.Vt "unsigned char" ) 54in object 55.Fa b , 56limited to at most 57.Fa len 58characters. 59.Pp 60The 61.Fn memrchr 62function behaves like 63.Fn memchr , 64except that it locates the last occurrence of 65.Fa c 66in object 67.Fa b , 68limited to the first 69.Fa len 70characters. 71.Sh RETURN VALUES 72The 73.Fn memchr 74and 75.Fn memrchr 76functions return a pointer to the byte located, or 77.Dv NULL 78if no such byte exists within 79.Fa len 80bytes. 81.Sh SEE ALSO 82.Xr memmem 3 , 83.Xr strchr 3 , 84.Xr strcspn 3 , 85.Xr strpbrk 3 , 86.Xr strrchr 3 , 87.Xr strsep 3 , 88.Xr strspn 3 , 89.Xr strstr 3 , 90.Xr strtok 3 , 91.Xr wmemchr 3 92.Sh STANDARDS 93The 94.Fn memchr 95function 96conforms to 97.St -isoC . 98.Pp 99The 100.Fn memrchr 101function is a GNU extension and conforms to no standard. 102.Sh HISTORY 103The 104.Fn memrchr 105function first appeared in GNU libc 2.1.91, this implementation 106first appeared in 107.Fx 6.4 , 108coming from 109.Ox 4.3 . 110