1.\" $OpenBSD: getcwd.3,v 1.16 2014/01/21 03:15:45 schwarze Exp $ 2.\" 3.\" Copyright (c) 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.Dd $Mdocdate: January 21 2014 $ 31.Dt GETCWD 3 32.Os 33.Sh NAME 34.Nm getcwd , 35.Nm getwd 36.Nd get working directory pathname 37.Sh SYNOPSIS 38.In unistd.h 39.Ft char * 40.Fn getcwd "char *buf" "size_t size" 41.Ft char * 42.Fn getwd "char *buf" 43.Sh DESCRIPTION 44The 45.Fn getcwd 46function copies the absolute pathname of the current working directory 47into the memory referenced by 48.Fa buf 49and returns a pointer to 50.Fa buf . 51The 52.Fa size 53argument is the size, in bytes, of the array referenced by 54.Fa buf . 55.Pp 56If 57.Fa buf 58is 59.Dv NULL , 60space is allocated as necessary to store the pathname. 61This space may later be 62.Xr free 3 Ns 'd. 63.Pp 64The function 65.Fn getwd 66is a compatibility routine which calls 67.Fn getcwd 68with its 69.Fa buf 70argument and a size of 71.Dv PATH_MAX 72(as defined in the include 73file 74.In limits.h ) . 75Obviously, 76.Fa buf 77should be at least 78.Dv PATH_MAX 79bytes in length. 80.Pp 81These routines have traditionally been used by programs to save the 82name of a working directory for the purpose of returning to it. 83A much faster and less error-prone method of accomplishing this is to 84open the current directory 85.Pq Pa \&. 86and use the 87.Xr fchdir 2 88function to return. 89.Sh RETURN VALUES 90Upon successful completion, a pointer to the pathname is returned. 91Otherwise a null pointer is returned and the global variable 92.Va errno 93is set to indicate the error. 94In addition, 95.Fn getwd 96copies the error message associated with 97.Va errno 98into the memory referenced by 99.Fa buf . 100.Sh ERRORS 101The 102.Fn getwd 103function will fail if: 104.Bl -tag -width Er 105.It Bq Er EACCES 106Read or search permission was denied for a component of the pathname. 107.It Bq Er EINVAL 108The 109.Fa size 110argument is zero. 111.It Bq Er ENOENT 112A component of the pathname no longer exists. 113.It Bq Er ENOMEM 114Insufficient memory is available. 115.It Bq Er ERANGE 116The 117.Fa size 118argument is greater than zero but smaller than the length of the pathname 119plus 1. 120.El 121.Sh SEE ALSO 122.Xr pwd 1 , 123.Xr chdir 2 , 124.Xr fchdir 2 , 125.Xr malloc 3 , 126.Xr strerror 3 127.Sh STANDARDS 128The 129.Fn getcwd 130function conforms to 131.St -p1003.1-2001 . 132The ability to specify a null pointer and have 133.Fn getcwd 134allocate memory as necessary is an extension. 135.Sh HISTORY 136The 137.Fn getwd 138function first appeared in 139.Bx 4.0 , 140and 141.Fn getcwd 142in 143.Bx 4.3 Net2 . 144.Sh BUGS 145The 146.Fn getwd 147function does not do sufficient error checking and is not able to return very 148long, but valid, paths. 149It is provided for compatibility. 150