xref: /freebsd/lib/libc/gen/dirname.3 (revision 5c564bae0a7655b1a517f322ad410a743e98e8d2)

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.\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
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.\" $OpenBSD: dirname.3,v 1.9 2000/04/18 03:01:25 aaron Exp $
.\" $FreeBSD$
.\"
.Dd August 17, 1997
.Dt DIRNAME 3
.Os
.Sh NAME
.Nm dirname
.Nd extract the directory portition of a pathname
.Sh SYNOPSIS
.In libgen.h
.Ft char *
.Fn dirname "const char *path"
.Sh DESCRIPTION
The
.Fn dirname
function
is the converse of
.Xr basename 3 ;
it returns a pointer to the parent directory of the pathname pointed to by
.Fa path .
Any trailing
.Sq \&/
characters are not counted as part of the directory
name.
If
.Fa path
is a null pointer, the empty string, or contains no
.Sq \&/
characters,
.Fn dirname
returns a pointer to the string
.Qq \&. ,
signifying the current directory.
.Sh RETURN VALUES
On successful completion,
.Fn dirname
returns a pointer to the parent directory of
.Fa path .
.Pp
If
.Fn dirname
fails, a null pointer is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
The following error codes may be set in
.Va errno :
.Bl -tag -width Er
.It Bq Er ENAMETOOLONG
The path component to be returned was larger than
.Dv MAXPATHLEN .
.El
.Sh WARNINGS
The
.Fn dirname
function
returns a pointer to internal static storage space that will be overwritten
by subsequent calls (each function has its own separate storage).
.Pp
Other vendor implementations of
.Fn dirname
may modify the contents of the string passed to
.Fn dirname ;
this should be taken into account when writing code which calls this function
if portability is desired.
.Sh SEE ALSO
.Xr basename 1 ,
.Xr dirname 1 ,
.Xr basename 3
.Sh STANDARDS
The
.Fn dirname
function conforms to
.St -xpg4.2 .
.Sh HISTORY
The
.Fn dirname
function first appeared in
.Ox 2.2
and
.Fx 4.2 .
.Sh AUTHORS
Todd C. Miller <Todd.Miller@courtesan.com>