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. 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.Dd March 20, 2011 31.Dt INDEX 3 32.Os 33.Sh NAME 34.Nm index , rindex 35.Nd locate character in string 36.Sh LIBRARY 37.Lb libc 38.Sh SYNOPSIS 39.In strings.h 40.Ft "char *" 41.Fn index "const char *s" "int c" 42.Ft "char *" 43.Fn rindex "const char *s" "int c" 44.Sh DESCRIPTION 45.Bf -symbolic 46The 47.Fn index 48and 49.Fn rindex 50functions have been deprecated in favor of 51.Xr strchr 3 52and 53.Xr strrchr 3 . 54.Ef 55.Pp 56The 57.Fn index 58function 59locates the first occurrence of 60.Fa c 61(converted to a 62.Vt char ) 63in the string pointed to by 64.Fa s . 65The terminating null character is considered part of the string; 66therefore if 67.Fa c 68is 69.Ql \e0 , 70the functions locate the terminating 71.Ql \e0 . 72.Pp 73The 74.Fn rindex 75function is identical to 76.Fn index , 77except it locates the last occurrence of 78.Fa c . 79.Sh RETURN VALUES 80The functions 81.Fn index 82and 83.Fn rindex 84return a pointer to the located character, or 85.Dv NULL 86if the character does not appear in the string. 87.Sh SEE ALSO 88.Xr memchr 3 , 89.Xr strchr 3 , 90.Xr strcspn 3 , 91.Xr strpbrk 3 , 92.Xr strrchr 3 , 93.Xr strsep 3 , 94.Xr strspn 3 , 95.Xr strstr 3 , 96.Xr strtok 3 97.Sh HISTORY 98The 99.Fn index 100and 101.Fn rindex 102functions appeared in 103.At v6 . 104Their prototypes existed previously in 105.In string.h 106before they were moved to 107.In strings.h 108for 109.St -p1003.1-2001 110compliance. 111The functions are not specified by 112.St -p1003.1-2008 . 113