freebsd-dev/lib/libc/string/index.3
Robert Drehmel 425289a9db - Update the manual pages of index() and rindex() to show
<strings.h> as the associated header file.
   The prototypes have been moved there from <string.h> because
   POSIX.1-2001 said so.
 - Conditionally include either <strings.h> or <string.h> based
   on whether the [r]index() or str[r]chr() functions are
   compiled, respectively.
 - Style(9) tells us to
    - put a space after the return keyword
    - to check for a NUL character without using the ! operator.
    - use NULL instead of (type *)NULL where the compiler knows
      the type.
   Apply these rules.
 - Rather use ANSI-C function definitions than K&R ones.
 - For index(3), correct second function argument's type; it was
   declared to be a `const char' before and is now an `int'.
2002-08-30 19:42:07 +00:00

91 lines
2.8 KiB
Groff

.\" 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 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
.Em 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.