1.\" $NetBSD: realpath.3,v 1.8 2002/02/07 07:00:16 ross Exp $ 2.\" 3.\" Copyright (c) 1994 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" This code is derived from software contributed to Berkeley by 7.\" Jan-Simon Pendry. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. All advertising materials mentioning features or use of this software 18.\" must display the following acknowledgement: 19.\" This product includes software developed by the University of 20.\" California, Berkeley and its contributors. 21.\" 4. Neither the name of the University nor the names of its contributors 22.\" may be used to endorse or promote products derived from this software 23.\" without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35.\" SUCH DAMAGE. 36.\" 37.\" from: @(#)realpath.3 8.2 (Berkeley) 2/16/94 38.\" 39.Dd February 16, 1994 40.Dt REALPATH 3 41.Os 42.Sh NAME 43.Nm realpath 44.Nd returns the canonicalized absolute pathname 45.Sh LIBRARY 46.Lb libc 47.Sh SYNOPSIS 48.Fd #include \*[Lt]sys/param.h\*[Gt] 49.Fd #include \*[Lt]stdlib.h\*[Gt] 50.Ft "char *" 51.Fn realpath "const char *pathname" "char resolvedname[MAXPATHLEN]" 52.Sh DESCRIPTION 53The 54.Fn realpath 55function resolves all symbolic links, extra 56.Dq / 57characters and references to 58.Pa /./ 59and 60.Pa /../ 61in 62.Fa pathname , 63and copies the resulting absolute pathname into 64the memory referenced by 65.Fa resolvedname . 66The 67.Fa resolvedname 68argument 69.Em must 70refer to a buffer capable of storing at least 71.Dv MAXPATHLEN 72characters. 73.Pp 74The 75.Fn realpath 76function will resolve both absolute and relative paths 77and return the absolute pathname corresponding to 78.Fa pathname . 79All but the last component of 80.Fa pathname 81must exist when 82.Fn realpath 83is called. 84.Sh RETURN VALUES 85The 86.Fn realpath 87function returns 88.Fa resolved_name 89on success. 90If an error occurs, 91.Fn realpath 92returns 93.Dv NULL , 94and 95.Fa resolved_name 96contains the pathname which caused the problem. 97.Sh ERRORS 98The function 99.Fn realpath 100may fail and set the external variable 101.Va errno 102for any of the errors specified for the library functions 103.Xr chdir 2 , 104.Xr close 2 , 105.Xr fchdir 2 , 106.Xr lstat 2 , 107.Xr open 2 , 108.Xr readlink 2 109and 110.Xr getcwd 3 . 111.Sh SEE ALSO 112.Xr getcwd 3 113.Sh HISTORY 114The 115.Fn realpath 116function call first appeared in 117.Bx 4.4 . 118.Sh BUGS 119This implementation of 120.Fn realpath 121differs slightly from the Solaris implementation. 122The 123.Bx 4.4 124version always returns absolute pathnames, 125whereas the Solaris implementation will, 126under certain circumstances, return a relative 127.Fa resolved_path 128when given a relative 129.Fa pathname . 130