.\" 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.
-.\" 3. All advertising materials mentioning features or use of this software
-.\" must display the following acknowledgement:
-.\" This product includes software developed by the University of
-.\" California, Berkeley and its contributors.
.\" 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.
.\" SUCH DAMAGE.
.\"
.\" @(#)realpath.3 8.2 (Berkeley) 2/16/94
-.\" $FreeBSD: src/lib/libc/stdlib/realpath.3,v 1.13 2003/03/27 20:48:53 fjoe Exp $
+.\" $FreeBSD: src/lib/libc/stdlib/realpath.3,v 1.14 2007/01/09 00:28:10 imp Exp $
.\"
-.Dd February 16, 1994
+.Dd April 5, 2008
.Dt REALPATH 3
.Os
.Sh NAME
.Nm realpath
.Nd returns the canonicalized absolute pathname
-.Sh LIBRARY
-.Lb libc
+.\" .Sh LIBRARY
+.\" .Lb libc
.Sh SYNOPSIS
-.In sys/param.h
.In stdlib.h
.Ft "char *"
-.Fn realpath "const char *pathname" "char resolved_path[PATH_MAX]"
+.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
+characters, and references to
.Pa /./
and
.Pa /../
in
-.Fa pathname ,
-and copies the resulting absolute pathname into
-the memory referenced by
-.Fa resolved_path .
-The
-.Fa resolved_path
+.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.
+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 pathname .
-All but the last component of
-.Fa pathname
+.Fa file_name .
+All components of
+.Fa file_name
must exist when
.Fn realpath
is called.
.Sh "RETURN VALUES"
-The
+On success, the
.Fn realpath
-function returns
-.Fa resolved_path
-on success.
+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 ,
-and
-.Fa resolved_path
+.Dv NULL .
+If
+.Fa resolved_name
+was non-NULL, it will
contains the pathname which caused the problem.
+.Sh VARIANTS
+Defining
+.Dv _DARWIN_C_SOURCE
+or
+.Dv _DARWIN_BETTER_REALPATH
+before including stdio.h will cause the provided implementation of
+.Fn realpath
+to use F_GETPATH from
+.Xr fcntl 2
+to discover the path.
.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 readlink 2 ,
+.Xr stat 2 ,
and
-.Xr getcwd 3 .
-.Sh CAVEATS
-This implementation of
+.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
-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_path
-when given a relative
-.Fa pathname .
+is called.
.Sh "SEE ALSO"
-.Xr getcwd 3
+.Xr free 3 ,
+.Xr getcwd 3 ,
+.Xr compat 5
.Sh HISTORY
The
.Fn realpath
projects / apple / libc.git / blobdiff