1.\" Copyright (c) 1994 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" Jan-Simon Pendry. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 4. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)realpath.3 8.2 (Berkeley) 2/16/94 32.\" $FreeBSD$ 33.\" 34.Dd April 19, 2010 35.Dt REALPATH 3 36.Os 37.Sh NAME 38.Nm realpath 39.Nd returns the canonicalized absolute pathname 40.Sh LIBRARY 41.Lb libc 42.Sh SYNOPSIS 43.In sys/param.h 44.In stdlib.h 45.Ft "char *" 46.Fn realpath "const char *pathname" "char *resolved_path" 47.Sh DESCRIPTION 48The 49.Fn realpath 50function resolves all symbolic links, extra 51.Dq / 52characters and references to 53.Pa /./ 54and 55.Pa /../ 56in 57.Fa pathname , 58and copies the resulting absolute pathname into 59the memory pointed to by 60.Fa resolved_path . 61The 62.Fa resolved_path 63argument 64.Em must 65point to a buffer capable of storing at least 66.Dv PATH_MAX 67characters, or be 68.Dv NULL . 69.Pp 70The 71.Fn realpath 72function will resolve both absolute and relative paths 73and return the absolute pathname corresponding to 74.Fa pathname . 75All but the last component of 76.Fa pathname 77must exist when 78.Fn realpath 79is called. 80.Sh "RETURN VALUES" 81The 82.Fn realpath 83function returns 84.Fa resolved_path 85on success. 86If the function was supplied 87.Dv NULL 88as 89.Fa resolved_path , 90and operation did not cause errors, the returned value is 91a null-terminated string in a buffer allocated by a call to 92.Fn malloc 3 . 93If an error occurs, 94.Fn realpath 95returns 96.Dv NULL , 97and if 98.Fa resolved_path 99is not 100.Dv NULL , 101the array that it points to contains the pathname which caused the problem. 102.Sh ERRORS 103The function 104.Fn realpath 105may fail and set the external variable 106.Va errno 107for any of the errors specified for the library functions 108.Xr lstat 2 , 109.Xr readlink 2 110and 111.Xr getcwd 3 . 112.Sh SEE ALSO 113.Xr getcwd 3 114.\" .Sh STANDARDS 115.\" The 116.\" .Fn realpath 117.\" function conforms to 118.\" .St -p1003.1-2001 . 119.Sh HISTORY 120The 121.Fn realpath 122function first appeared in 123.Bx 4.4 . 124.Sh CAVEATS 125This implementation of 126.Fn realpath 127differs slightly from the Solaris implementation. 128The 129.Bx 4.4 130version always returns absolute pathnames, 131whereas the Solaris implementation will, 132under certain circumstances, return a relative 133.Fa resolved_path 134when given a relative 135.Fa pathname . 136