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.\" Jan-Simon Pendry.
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.\"	$OpenBSD: realpath.3,v 1.19 2014/01/20 22:40:06 schwarze Exp $
.\"
.Dd $Mdocdate: January 20 2014 $
.Dt REALPATH 3
.Os
.Sh NAME
.Nm realpath
.Nd returns the canonicalized absolute pathname
.Sh SYNOPSIS
.In limits.h
.In stdlib.h
.Ft "char *"
.Fn realpath "const char *pathname" "char *resolved"
.Sh DESCRIPTION
The
.Fn realpath
function resolves all symbolic links, extra
.Dq /
characters and references to
.Pa /./
and
.Pa /../
in
.Fa pathname ,
and copies the resulting absolute pathname into the memory referenced by
.Fa resolved .
The
.Fa resolved
argument
.Em must
refer to a buffer capable of storing at least
.Dv PATH_MAX
characters, or be
.Dv NULL .
.Pp
The
.Fn realpath
function will resolve both absolute and relative paths
and return the absolute pathname corresponding to
.Fa pathname .
All but the last component of
.Fa pathname
must exist when
.Fn realpath
is called.
.Sh RETURN VALUES
The
.Fn realpath
function returns
.Fa resolved
on success.
If
.Fa resolved
is
.Dv NULL
and no error occurred, then
.Fn realpath
returns a NUL-terminated string in a newly allocated buffer.
If an error occurs,
.Fn realpath
returns
.Dv NULL
and the contents of
.Fa resolved
are undefined.
.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 lstat 2 ,
.Xr readlink 2 ,
and
.Xr getcwd 3 .
.Sh SEE ALSO
.Xr readlink 1 ,
.Xr getcwd 3
.Sh STANDARDS
The
.Fn realpath
function conforms to
.St -p1003.1-2008 .
.Sh HISTORY
The
.Fn realpath
function call first appeared in
.Bx 4.4 .
.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
when given a relative
.Fa pathname .