freebsd-dev/lib/libc/string/index.3
Ed Maste 3fb3b97c4d Renumber clauses to reduce diffs to other versions
NetBSD, OpenBSD, and Android's Bionic number the clauses 1 through 3,
so follow suit to make comparison easier.
2013-05-28 20:57:40 +00:00

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.\" Copyright (c) 1990, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" Chris Torek.
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.\" @(#)index.3 8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
.\"
.Dd March 20, 2011
.Dt INDEX 3
.Os
.Sh NAME
.Nm index , rindex
.Nd locate character in string
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In strings.h
.Ft "char *"
.Fn index "const char *s" "int c"
.Ft "char *"
.Fn rindex "const char *s" "int c"
.Sh DESCRIPTION
.Bf -symbolic
The
.Fn index
and
.Fn rindex
functions have been deprecated in favor of
.Xr strchr 3
and
.Xr strrchr 3 .
.Ef
.Pp
The
.Fn index
function
locates the first occurrence of
.Fa c
(converted to a
.Vt char )
in the string pointed to by
.Fa s .
The terminating null character is considered part of the string;
therefore if
.Fa c
is
.Ql \e0 ,
the functions locate the terminating
.Ql \e0 .
.Pp
The
.Fn rindex
function is identical to
.Fn index ,
except it locates the last occurrence of
.Fa c .
.Sh RETURN VALUES
The functions
.Fn index
and
.Fn rindex
return a pointer to the located character, or
.Dv NULL
if the character does not appear in the string.
.Sh SEE ALSO
.Xr memchr 3 ,
.Xr strchr 3 ,
.Xr strcspn 3 ,
.Xr strpbrk 3 ,
.Xr strrchr 3 ,
.Xr strsep 3 ,
.Xr strspn 3 ,
.Xr strstr 3 ,
.Xr strtok 3
.Sh HISTORY
The
.Fn index
and
.Fn rindex
functions appeared in
.At v6 .
Their prototypes existed previously in
.In string.h
before they were moved to
.In strings.h
for
.St -p1003.1-2001
compliance.
The functions are not specified by
.St -p1003.1-2008 .