[apple/libc.git] / gen / FreeBSD / getcwd.3

.\" Copyright (c) 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)getcwd.3	8.2 (Berkeley) 12/11/93
.\" $FreeBSD: src/lib/libc/gen/getcwd.3,v 1.16 2003/09/08 19:57:14 ru Exp $
.\"
.Dd November 24, 1997
.Dt GETCWD 3
.Os
.Sh NAME
.Nm getcwd ,
.Nm getwd
.Nd get working directory pathname
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In unistd.h
.Ft char *
.Fn getcwd "char *buf" "size_t size"
.Ft char *
.Fn getwd "char *buf"
.Sh DESCRIPTION
The
.Fn getcwd
function copies the absolute pathname of the current working directory
into the memory referenced by
.Fa buf
and returns a pointer to
.Fa buf .
The
.Fa size
argument is the size, in bytes, of the array referenced by
.Fa buf .
.Pp
If
.Fa buf
is
.Dv NULL ,
space is allocated as necessary to store the pathname.
This space may later be
.Xr free 3 Ns 'd .
.Pp
The function
.Fn getwd
is a compatibility routine which calls
.Fn getcwd
with its
.Fa buf
argument and a size of
.Dv MAXPATHLEN
(as defined in the include
file
.In sys/param.h ) .
Obviously,
.Fa buf
should be at least
.Dv MAXPATHLEN
bytes in length.
.Pp
These routines have traditionally been used by programs to save the
name of a working directory for the purpose of returning to it.
A much faster and less error-prone method of accomplishing this is to
open the current directory
.Pq Ql .\&
and use the
.Xr fchdir 2
function to return.
.Sh RETURN VALUES
Upon successful completion, a pointer to the pathname is returned.
Otherwise a
.Dv NULL
pointer is returned and the global variable
.Va errno
is set to indicate the error.
In addition,
.Fn getwd
copies the error message associated with
.Va errno
into the memory referenced by
.Fa buf .
.Sh ERRORS
The
.Fn getcwd
function
will fail if:
.Bl -tag -width Er
.It Bq Er EACCES
Read or search permission was denied for a component of the pathname.
.It Bq Er EINVAL
The
.Fa size
argument is zero.
.It Bq Er ENOENT
A component of the pathname no longer exists.
.It Bq Er ENOMEM
Insufficient memory is available.
.It Bq Er ERANGE
The
.Fa size
argument is greater than zero but smaller than the length of the pathname
plus 1.
.El
.Sh SEE ALSO
.Xr chdir 2 ,
.Xr fchdir 2 ,
.Xr malloc 3 ,
.Xr strerror 3
.Sh STANDARDS
The
.Fn getcwd
function
conforms to
.St -p1003.1-90 .
The ability to specify a
.Dv NULL
pointer and have
.Fn getcwd
allocate memory as necessary is an extension.
.Sh HISTORY
The
.Fn getwd
function appeared in
.Bx 4.0 .
.Sh BUGS
The
.Fn getwd
function
does not do sufficient error checking and is not able to return very
long, but valid, paths.
It is provided for compatibility.
Commit	Line	Data
5b2abdfb A	1	.\" Copyright (c) 1991, 1993
	2	.\" The Regents of the University of California. All rights reserved.
	3	.\"
	4	.\" Redistribution and use in source and binary forms, with or without
	5	.\" modification, are permitted provided that the following conditions
	6	.\" are met:
	7	.\" 1. Redistributions of source code must retain the above copyright
	8	.\" notice, this list of conditions and the following disclaimer.
	9	.\" 2. Redistributions in binary form must reproduce the above copyright
	10	.\" notice, this list of conditions and the following disclaimer in the
	11	.\" documentation and/or other materials provided with the distribution.
	12	.\" 3. All advertising materials mentioning features or use of this software
	13	.\" must display the following acknowledgement:
	14	.\" This product includes software developed by the University of
	15	.\" California, Berkeley and its contributors.
	16	.\" 4. Neither the name of the University nor the names of its contributors
	17	.\" may be used to endorse or promote products derived from this software
	18	.\" without specific prior written permission.
	19	.\"
	20	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	.\" SUCH DAMAGE.
	31	.\"
	32	.\" @(#)getcwd.3 8.2 (Berkeley) 12/11/93
3d9156a7	33	.\" $FreeBSD: src/lib/libc/gen/getcwd.3,v 1.16 2003/09/08 19:57:14 ru Exp $
5b2abdfb A	34	.\"
	35	.Dd November 24, 1997
	36	.Dt GETCWD 3
	37	.Os
	38	.Sh NAME
	39	.Nm getcwd ,
	40	.Nm getwd
	41	.Nd get working directory pathname
	42	.Sh LIBRARY
	43	.Lb libc
	44	.Sh SYNOPSIS
	45	.In unistd.h
	46	.Ft char *
	47	.Fn getcwd "char *buf" "size_t size"
	48	.Ft char *
	49	.Fn getwd "char *buf"
	50	.Sh DESCRIPTION
	51	The
	52	.Fn getcwd
	53	function copies the absolute pathname of the current working directory
	54	into the memory referenced by
	55	.Fa buf
	56	and returns a pointer to
	57	.Fa buf .
	58	The
	59	.Fa size
	60	argument is the size, in bytes, of the array referenced by
	61	.Fa buf .
	62	.Pp
	63	If
	64	.Fa buf
	65	is
	66	.Dv NULL ,
	67	space is allocated as necessary to store the pathname.
	68	This space may later be
	69	.Xr free 3 Ns 'd .
	70	.Pp
	71	The function
	72	.Fn getwd
	73	is a compatibility routine which calls
	74	.Fn getcwd
	75	with its
	76	.Fa buf
	77	argument and a size of
	78	.Dv MAXPATHLEN
	79	(as defined in the include
	80	file
3d9156a7	81	.In sys/param.h ) .
5b2abdfb A	82	Obviously,
	83	.Fa buf
	84	should be at least
	85	.Dv MAXPATHLEN
	86	bytes in length.
	87	.Pp
	88	These routines have traditionally been used by programs to save the
	89	name of a working directory for the purpose of returning to it.
	90	A much faster and less error-prone method of accomplishing this is to
	91	open the current directory
	92	.Pq Ql .\&
	93	and use the
	94	.Xr fchdir 2
	95	function to return.
	96	.Sh RETURN VALUES
	97	Upon successful completion, a pointer to the pathname is returned.
	98	Otherwise a
	99	.Dv NULL
	100	pointer is returned and the global variable
	101	.Va errno
	102	is set to indicate the error.
	103	In addition,
	104	.Fn getwd
	105	copies the error message associated with
	106	.Va errno
	107	into the memory referenced by
	108	.Fa buf .
	109	.Sh ERRORS
	110	The
	111	.Fn getcwd
	112	function
	113	will fail if:
	114	.Bl -tag -width Er
	115	.It Bq Er EACCES
	116	Read or search permission was denied for a component of the pathname.
	117	.It Bq Er EINVAL
	118	The
	119	.Fa size
	120	argument is zero.
	121	.It Bq Er ENOENT
	122	A component of the pathname no longer exists.
	123	.It Bq Er ENOMEM
	124	Insufficient memory is available.
	125	.It Bq Er ERANGE
	126	The
	127	.Fa size
	128	argument is greater than zero but smaller than the length of the pathname
	129	plus 1.
	130	.El
	131	.Sh SEE ALSO
	132	.Xr chdir 2 ,
	133	.Xr fchdir 2 ,
	134	.Xr malloc 3 ,
	135	.Xr strerror 3
	136	.Sh STANDARDS
	137	The
	138	.Fn getcwd
	139	function
	140	conforms to
	141	.St -p1003.1-90 .
	142	The ability to specify a
	143	.Dv NULL
	144	pointer and have
	145	.Fn getcwd
146	allocate memory as necessary is an extension.
147	.Sh HISTORY
148	The
149	.Fn getwd
150	function appeared in
151	.Bx 4.0 .
152	.Sh BUGS
153	The
154	.Fn getwd
155	function
156	does not do sufficient error checking and is not able to return very
157	long, but valid, paths.
158	It is provided for compatibility.