.\" Copyright (c) 1994 .\" The Regents of the University of California. All rights reserved. .\" .\" This code is derived from software contributed to Berkeley by .\" Jan-Simon Pendry. .\" .\" 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. .\" .\" @(#)realpath.3 8.2 (Berkeley) 2/16/94 .\" $FreeBSD: src/lib/libc/stdlib/realpath.3,v 1.14 2007/01/09 00:28:10 imp Exp $ .\" .Dd April 5, 2008 .Dt REALPATH 3 .Os .Sh NAME .Nm realpath .Nd returns the canonicalized absolute pathname .\" .Sh LIBRARY .\" .Lb libc .Sh SYNOPSIS .In stdlib.h .Ft "char *" .Fo realpath .Fa "const char *restrict file_name" .Fa "char *restrict resolved_name" .Fc .Sh DESCRIPTION The .Fn realpath function resolves all symbolic links, extra .Dq / characters, and references to .Pa /./ and .Pa /../ in .Fa file_name . If the .Fa resolved_name argument is non-NULL, the resulting absolute pathname is copied there (it .Em must refer to a buffer capable of storing at least .Dv PATH_MAX characters). .Pp As a permitted extension to the standard, if .Fa resolved_name is NULL, memory is allocated for the resulting absolute pathname, and is returned by .Fn realpath . This memory should be freed by a call to .Xr free 3 when no longer needed. .Pp The .Fn realpath function will resolve both absolute and relative paths and return the absolute pathname corresponding to .Fa file_name . All components of .Fa file_name must exist when .Fn realpath is called. .Sh "RETURN VALUES" On success, the .Fn realpath function returns the address of the resulting absolute pathname, which is .Fa resolved_name if it was non-NULL, or the address of newly allocated memory. If an error occurs, .Fn realpath returns .Dv NULL . If .Fa resolved_name was non-NULL, it will contains the pathname which caused the problem. .Sh ERRORS The function .Fn realpath may fail and set the external variable .Va errno for any of the errors specified for the library functions .Xr alloca 3 , .Xr getattrlist 2 , .Xr getcwd 3 , .Xr lstat 2 , .Xr readlink 2 , .Xr stat 2 , and .Xr strdup 3 . .\" .Sh CAVEATS .\" This implementation of .\" .Fn realpath .\" differs slightly from the Solaris implementation. .\" The .\" .Bx 4.4 .\" version always returns absolute pathnames, .\" whereas the Solaris implementation will, .\" under certain circumstances, return a relative .\" .Fa resolved_name .\" when given a relative .\" .Fa file_name . .Sh LEGACY SYNOPSIS .Fd #include <sys/param.h> .Fd #include <stdlib.h> .Pp The include file .In sys/param.h is necessary. .Sh LEGACY DESCRIPTION In legacy mode, the last component of .Fa file_name does not need to exist when .Fn realpath is called. .Sh "SEE ALSO" .Xr free 3 , .Xr getcwd 3 , .Xr compat 5 .Sh HISTORY The .Fn realpath function first appeared in .Bx 4.4 .