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File::Spec::Mac(3pm)   Perl Programmers Reference Guide	  File::Spec::Mac(3pm)

NAME
       File::Spec::Mac - File::Spec for Mac OS (Classic)

SYNOPSIS
	require File::Spec::Mac; # Done internally by File::Spec if needed

DESCRIPTION
       Methods for manipulating file specifications.

METHODS
       canonpath
	 On Mac OS, there's nothing to be done. Returns what it's given.

       catdir()
	 Concatenate two or more directory names to form a path separated by
	 colons (":") ending with a directory. Resulting paths are relative by
	 default, but can be forced to be absolute (but avoid this, see
	 below). Automatically puts a trailing ":" on the end of the complete
	 path, because that's what's done in MacPerl's environment and helps
	 to distinguish a file path from a directory path.

	 IMPORTANT NOTE: Beginning with version 1.3 of this module, the
	 resulting path is relative by default and not absolute. This decision
	 was made due to portability reasons. Since "File::Spec->catdir()"
	 returns relative paths on all other operating systems, it will now
	 also follow this convention on Mac OS. Note that this may break some
	 existing scripts.

	 The intended purpose of this routine is to concatenate directory
	 names.	 But because of the nature of Macintosh paths, some additional
	 possibilities are allowed to make using this routine give reasonable
	 results for some common situations. In other words, you are also
	 allowed to concatenate paths instead of directory names (strictly
	 speaking, a string like ":a" is a path, but not a name, since it
	 contains a punctuation character ":").

	 So, beside calls like

	     catdir("a") = ":a:"
	     catdir("a","b") = ":a:b:"
	     catdir() = ""		      (special case)

	 calls like the following

	     catdir(":a:") = ":a:"
	     catdir(":a","b") = ":a:b:"
	     catdir(":a:","b") = ":a:b:"
	     catdir(":a:",":b:") = ":a:b:"
	     catdir(":") = ":"

	 are allowed.

	 Here are the rules that are used in "catdir()"; note that we try to
	 be as compatible as possible to Unix:

	 1.
	   The resulting path is relative by default, i.e. the resulting path
	   will have a leading colon.

	 2.
	   A trailing colon is added automatically to the resulting path, to
	   denote a directory.

	 3.
	   Generally, each argument has one leading ":" and one trailing ":"
	   removed (if any). They are then joined together by a ":". Special
	   treatment applies for arguments denoting updir paths like "::lib:",
	   see (4), or arguments consisting solely of colons ("colon paths"),
	   see (5).

	 4.
	   When an updir path like ":::lib::" is passed as argument, the
	   number of directories to climb up is handled correctly, not
	   removing leading or trailing colons when necessary. E.g.

	       catdir(":::a","::b","c")	   = ":::a::b:c:"
	       catdir(":::a::","::b","c")  = ":::a:::b:c:"

	 5.
	   Adding a colon ":" or empty string "" to a path at any position
	   doesn't alter the path, i.e. these arguments are ignored. (When a
	   "" is passed as the first argument, it has a special meaning, see
	   (6)). This way, a colon ":" is handled like a "." (curdir) on Unix,
	   while an empty string "" is generally ignored (see
	   "Unix->canonpath()" ). Likewise, a "::" is handled like a ".."
	   (updir), and a ":::" is handled like a "../.." etc.	E.g.

	       catdir("a",":",":","b")	 = ":a:b:"
	       catdir("a",":","::",":b") = ":a::b:"

	 6.
	   If the first argument is an empty string "" or is a volume name,
	   i.e. matches the pattern /^[^:]+:/, the resulting path is absolute.

	 7.
	   Passing an empty string "" as the first argument to "catdir()" is
	   like passing"File::Spec->rootdir()" as the first argument, i.e.

	       catdir("","a","b")	   is the same as

	       catdir(rootdir(),"a","b").

	   This is true on Unix, where "catdir("","a","b")" yields "/a/b" and
	   "rootdir()" is "/". Note that "rootdir()" on Mac OS is the startup
	   volume, which is the closest in concept to Unix' "/". This should
	   help to run existing scripts originally written for Unix.

	 8.
	   For absolute paths, some cleanup is done, to ensure that the volume
	   name isn't immediately followed by updirs. This is invalid, because
	   this would go beyond "root". Generally, these cases are handled
	   like their Unix counterparts:

	    Unix:
	       Unix->catdir("","")		   =  "/"
	       Unix->catdir("",".")		   =  "/"
	       Unix->catdir("","..")		   =  "/"	       # can't go beyond root
	       Unix->catdir("",".","..","..","a")  =  "/a"
	    Mac:
	       Mac->catdir("","")		   =  rootdir()		# (e.g. "HD:")
	       Mac->catdir("",":")		   =  rootdir()
	       Mac->catdir("","::")		   =  rootdir()		# can't go beyond root
	       Mac->catdir("",":","::","::","a")   =  rootdir() . "a:"	# (e.g. "HD:a:")

	   However, this approach is limited to the first arguments following
	   "root" (again, see "Unix->canonpath()" ). If there are more
	   arguments that move up the directory tree, an invalid path going
	   beyond root can be created.

	 As you've seen, you can force "catdir()" to create an absolute path
	 by passing either an empty string or a path that begins with a volume
	 name as the first argument. However, you are strongly encouraged not
	 to do so, since this is done only for backward compatibility. Newer
	 versions of File::Spec come with a method called "catpath()" (see
	 below), that is designed to offer a portable solution for the
	 creation of absolute paths.  It takes volume, directory and file
	 portions and returns an entire path. While "catdir()" is still
	 suitable for the concatenation of directory names, you are encouraged
	 to use "catpath()" to concatenate volume names and directory paths.
	 E.g.

	     $dir      = File::Spec->catdir("tmp","sources");
	     $abs_path = File::Spec->catpath("MacintoshHD:", $dir,"");

	 yields

	     "MacintoshHD:tmp:sources:" .

       catfile
	 Concatenate one or more directory names and a filename to form a
	 complete path ending with a filename. Resulting paths are relative by
	 default, but can be forced to be absolute (but avoid this).

	 IMPORTANT NOTE: Beginning with version 1.3 of this module, the
	 resulting path is relative by default and not absolute. This decision
	 was made due to portability reasons. Since "File::Spec->catfile()"
	 returns relative paths on all other operating systems, it will now
	 also follow this convention on Mac OS.	 Note that this may break some
	 existing scripts.

	 The last argument is always considered to be the file portion. Since
	 "catfile()" uses "catdir()" (see above) for the concatenation of the
	 directory portions (if any), the following with regard to relative
	 and absolute paths is true:

	     catfile("")     = ""
	     catfile("file") = "file"

	 but

	     catfile("","")	   = rootdir()	       # (e.g. "HD:")
	     catfile("","file")	   = rootdir() . file  # (e.g. "HD:file")
	     catfile("HD:","file") = "HD:file"

	 This means that "catdir()" is called only when there are two or more
	 arguments, as one might expect.

	 Note that the leading ":" is removed from the filename, so that

	     catfile("a","b","file")  = ":a:b:file"    and

	     catfile("a","b",":file") = ":a:b:file"

	 give the same answer.

	 To concatenate volume names, directory paths and filenames, you are
	 encouraged to use "catpath()" (see below).

       curdir
	 Returns a string representing the current directory. On Mac OS, this
	 is ":".

       devnull
	 Returns a string representing the null device. On Mac OS, this is
	 "Dev:Null".

       rootdir
	 Returns a string representing the root directory.  Under MacPerl,
	 returns the name of the startup volume, since that's the closest in
	 concept, although other volumes aren't rooted there. The name has a
	 trailing ":", because that's the correct specification for a volume
	 name on Mac OS.

	 If Mac::Files could not be loaded, the empty string is returned.

       tmpdir
	 Returns the contents of $ENV{TMPDIR}, if that directory exits or the
	 current working directory otherwise. Under MacPerl, $ENV{TMPDIR} will
	 contain a path like "MacintoshHD:Temporary Items:", which is a hidden
	 directory on your startup volume.

       updir
	 Returns a string representing the parent directory. On Mac OS, this
	 is "::".

       file_name_is_absolute
	 Takes as argument a path and returns true, if it is an absolute path.
	 If the path has a leading ":", it's a relative path. Otherwise, it's
	 an absolute path, unless the path doesn't contain any colons, i.e.
	 it's a name like "a". In this particular case, the path is considered
	 to be relative (i.e. it is considered to be a filename). Use ":" in
	 the appropriate place in the path if you want to distinguish
	 unambiguously. As a special case, the filename '' is always
	 considered to be absolute. Note that with version 1.2 of
	 File::Spec::Mac, this does no longer consult the local filesystem.

	 E.g.

	     File::Spec->file_name_is_absolute("a");		 # false (relative)
	     File::Spec->file_name_is_absolute(":a:b:");	 # false (relative)
	     File::Spec->file_name_is_absolute("MacintoshHD:");	 # true (absolute)
	     File::Spec->file_name_is_absolute("");		 # true (absolute)

       path
	 Returns the null list for the MacPerl application, since the concept
	 is usually meaningless under Mac OS. But if you're using the MacPerl
	 tool under MPW, it gives back $ENV{Commands} suitably split, as is
	 done in :lib:ExtUtils:MM_Mac.pm.

       splitpath
	     ($volume,$directories,$file) = File::Spec->splitpath( $path );
	     ($volume,$directories,$file) = File::Spec->splitpath( $path, $no_file );

	 Splits a path into volume, directory, and filename portions.

	 On Mac OS, assumes that the last part of the path is a filename
	 unless $no_file is true or a trailing separator ":" is present.

	 The volume portion is always returned with a trailing ":". The
	 directory portion is always returned with a leading (to denote a
	 relative path) and a trailing ":" (to denote a directory). The file
	 portion is always returned without a leading ":".  Empty portions are
	 returned as empty string ''.

	 The results can be passed to "catpath()" to get back a path
	 equivalent to (usually identical to) the original path.

       splitdir
	 The opposite of "catdir()".

	     @dirs = File::Spec->splitdir( $directories );

	 $directories should be only the directory portion of the path on
	 systems that have the concept of a volume or that have path syntax
	 that differentiates files from directories. Consider using
	 "splitpath()" otherwise.

	 Unlike just splitting the directories on the separator, empty
	 directory names ("") can be returned. Since "catdir()" on Mac OS
	 always appends a trailing colon to distinguish a directory path from
	 a file path, a single trailing colon will be ignored, i.e. there's no
	 empty directory name after it.

	 Hence, on Mac OS, both

	     File::Spec->splitdir( ":a:b::c:" );    and
	     File::Spec->splitdir( ":a:b::c" );

	 yield:

	     ( "a", "b", "::", "c")

	 while

	     File::Spec->splitdir( ":a:b::c::" );

	 yields:

	     ( "a", "b", "::", "c", "::")

       catpath
	     $path = File::Spec->catpath($volume,$directory,$file);

	 Takes volume, directory and file portions and returns an entire path.
	 On Mac OS, $volume, $directory and $file are concatenated.  A ':' is
	 inserted if need be. You may pass an empty string for each portion.
	 If all portions are empty, the empty string is returned. If $volume
	 is empty, the result will be a relative path, beginning with a ':'.
	 If $volume and $directory are empty, a leading ":" (if any) is
	 removed form $file and the remainder is returned. If $file is empty,
	 the resulting path will have a trailing ':'.

       abs2rel
	 Takes a destination path and an optional base path and returns a
	 relative path from the base path to the destination path:

	     $rel_path = File::Spec->abs2rel( $path ) ;
	     $rel_path = File::Spec->abs2rel( $path, $base ) ;

	 Note that both paths are assumed to have a notation that
	 distinguishes a directory path (with trailing ':') from a file path
	 (without trailing ':').

	 If $base is not present or '', then the current working directory is
	 used.	If $base is relative, then it is converted to absolute form
	 using "rel2abs()".  This means that it is taken to be relative to the
	 current working directory.

	 If $path and $base appear to be on two different volumes, we will not
	 attempt to resolve the two paths, and we will instead simply return
	 $path.	 Note that previous versions of this module ignored the volume
	 of $base, which resulted in garbage results part of the time.

	 If $base doesn't have a trailing colon, the last element of $base is
	 assumed to be a filename.  This filename is ignored.  Otherwise all
	 path components are assumed to be directories.

	 If $path is relative, it is converted to absolute form using
	 "rel2abs()".  This means that it is taken to be relative to the
	 current working directory.

	 Based on code written by Shigio Yamaguchi.

       rel2abs
	 Converts a relative path to an absolute path:

	     $abs_path = File::Spec->rel2abs( $path ) ;
	     $abs_path = File::Spec->rel2abs( $path, $base ) ;

	 Note that both paths are assumed to have a notation that
	 distinguishes a directory path (with trailing ':') from a file path
	 (without trailing ':').

	 If $base is not present or '', then $base is set to the current
	 working directory. If $base is relative, then it is converted to
	 absolute form using "rel2abs()". This means that it is taken to be
	 relative to the current working directory.

	 If $base doesn't have a trailing colon, the last element of $base is
	 assumed to be a filename.  This filename is ignored.  Otherwise all
	 path components are assumed to be directories.

	 If $path is already absolute, it is returned and $base is ignored.

	 Based on code written by Shigio Yamaguchi.

AUTHORS
       See the authors list in File::Spec. Mac OS support by Paul Schinder
       <schinder@pobox.com> and Thomas Wegner <wegner_thomas@yahoo.com>.

COPYRIGHT
       Copyright (c) 2004 by the Perl 5 Porters.  All rights reserved.

       This program is free software; you can redistribute it and/or modify it
       under the same terms as Perl itself.

SEE ALSO
       See File::Spec and File::Spec::Unix.  This package overrides the
       implementation of these methods, not the semantics.

perl v5.10.1			  2009-05-10		  File::Spec::Mac(3pm)
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