[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.
.\" 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
.\" $FreeBSD$
.\"
.Dd April 17, 2010
.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 and
.Fa size
is ignored.
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 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
.Pp
The
.Fn getcwd
function
may fail if:
.Bl -tag -width Er
.It Bq Er EACCES
Read or search permission was denied for a component of the pathname.
This is only checked in limited cases, depending on implementation details.
.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.
5b2abdfb A	12	.\" 4. Neither the name of the University nor the names of its contributors
	13	.\" may be used to endorse or promote products derived from this software
	14	.\" without specific prior written permission.
	15	.\"
	16	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	17	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	18	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	19	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	20	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	21	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	22	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	23	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	24	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	25	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	26	.\" SUCH DAMAGE.
	27	.\"
	28	.\" @(#)getcwd.3 8.2 (Berkeley) 12/11/93
b061a43b	29	.\" $FreeBSD$
5b2abdfb	30	.\"
b061a43b	31	.Dd April 17, 2010
5b2abdfb A	32	.Dt GETCWD 3
	33	.Os
	34	.Sh NAME
	35	.Nm getcwd ,
	36	.Nm getwd
	37	.Nd get working directory pathname
	38	.Sh LIBRARY
	39	.Lb libc
	40	.Sh SYNOPSIS
	41	.In unistd.h
	42	.Ft char *
	43	.Fn getcwd "char *buf" "size_t size"
	44	.Ft char *
	45	.Fn getwd "char *buf"
	46	.Sh DESCRIPTION
	47	The
	48	.Fn getcwd
	49	function copies the absolute pathname of the current working directory
	50	into the memory referenced by
	51	.Fa buf
	52	and returns a pointer to
	53	.Fa buf .
	54	The
	55	.Fa size
	56	argument is the size, in bytes, of the array referenced by
	57	.Fa buf .
	58	.Pp
	59	If
	60	.Fa buf
	61	is
	62	.Dv NULL ,
b061a43b A	63	space is allocated as necessary to store the pathname and
	64	.Fa size
	65	is ignored.
5b2abdfb A	66	This space may later be
	67	.Xr free 3 Ns 'd .
	68	.Pp
	69	The function
	70	.Fn getwd
	71	is a compatibility routine which calls
	72	.Fn getcwd
	73	with its
	74	.Fa buf
	75	argument and a size of
	76	.Dv MAXPATHLEN
	77	(as defined in the include
	78	file
3d9156a7	79	.In sys/param.h ) .
5b2abdfb A	80	Obviously,
	81	.Fa buf
	82	should be at least
	83	.Dv MAXPATHLEN
	84	bytes in length.
	85	.Pp
	86	These routines have traditionally been used by programs to save the
	87	name of a working directory for the purpose of returning to it.
	88	A much faster and less error-prone method of accomplishing this is to
	89	open the current directory
	90	.Pq Ql .\&
	91	and use the
	92	.Xr fchdir 2
	93	function to return.
	94	.Sh RETURN VALUES
	95	Upon successful completion, a pointer to the pathname is returned.
	96	Otherwise a
	97	.Dv NULL
	98	pointer is returned and the global variable
	99	.Va errno
	100	is set to indicate the error.
	101	In addition,
	102	.Fn getwd
	103	copies the error message associated with
	104	.Va errno
	105	into the memory referenced by
	106	.Fa buf .
	107	.Sh ERRORS
	108	The
	109	.Fn getcwd
	110	function
	111	will fail if:
	112	.Bl -tag -width Er
5b2abdfb A	113	.It Bq Er EINVAL
	114	The
	115	.Fa size
	116	argument is zero.
	117	.It Bq Er ENOENT
	118	A component of the pathname no longer exists.
	119	.It Bq Er ENOMEM
	120	Insufficient memory is available.
	121	.It Bq Er ERANGE
	122	The
	123	.Fa size
	124	argument is greater than zero but smaller than the length of the pathname
	125	plus 1.
	126	.El
b061a43b A	127	.Pp
	128	The
	129	.Fn getcwd
	130	function
	131	may fail if:
	132	.Bl -tag -width Er
	133	.It Bq Er EACCES
	134	Read or search permission was denied for a component of the pathname.
	135	This is only checked in limited cases, depending on implementation details.
	136	.El
5b2abdfb A	137	.Sh SEE ALSO
	138	.Xr chdir 2 ,
	139	.Xr fchdir 2 ,
	140	.Xr malloc 3 ,
	141	.Xr strerror 3
	142	.Sh STANDARDS
	143	The
	144	.Fn getcwd
	145	function
	146	conforms to
	147	.St -p1003.1-90 .
	148	The ability to specify a
	149	.Dv NULL
	150	pointer and have
	151	.Fn getcwd
	152	allocate memory as necessary is an extension.
	153	.Sh HISTORY
	154	The
	155	.Fn getwd
	156	function appeared in
	157	.Bx 4.0 .
	158	.Sh BUGS
	159	The
	160	.Fn getwd
	161	function
	162	does not do sufficient error checking and is not able to return very
	163	long, but valid, paths.
	164	It is provided for compatibility.