.\" Copyright (c) 1990, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
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.\" 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: src/lib/libc/string/index.3,v 1.8 2002/12/18 13:33:03 ru Exp $
.\"
.Dd June 4, 1993
.Dt INDEX 3
.Os
.Sh NAME
.Nm index
.Nd locate character in string
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In strings.h
.Ft char *
.Fn index "const char *s" "int c"
.Sh DESCRIPTION
The
.Fn index
function
locates the first character matching
.Fa c
(converted to a
.Vt char )
in the null-terminated string
.Fa s .
.Sh RETURN VALUES
A pointer to the character is returned if it is found; otherwise
.Dv NULL
is returned.
If
.Fa c
is '\e0',
.Fn index
locates the terminating '\e0'.
.Sh SEE ALSO
.Xr memchr 3 ,
.Xr rindex 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
A
.Fn index
function appeared in
.At v6 .
Its prototype existed previously in
.Aq Pa string.h
before it was moved to
.Aq Pa strings.h
for
.St -p1003.1-2001
compliance.