[p5sagit/p5-mst-13.2.git] / lib / Cwd.pm

package Cwd;
require 5.000;

=head1 NAME

getcwd - get pathname of current working directory

=head1 SYNOPSIS

    use Cwd;
    $dir = cwd;

    use Cwd;
    $dir = getcwd;

    use Cwd;
    $dir = fastgetcwd;

    use Cwd 'chdir';
    chdir "/tmp";
    print $ENV{'PWD'};

    use Cwd 'abs_path';	    # aka realpath()
    print abs_path($ENV{'PWD'});

    use Cwd 'fast_abs_path';
    print fast_abs_path($ENV{'PWD'});

=head1 DESCRIPTION

The getcwd() function re-implements the getcwd(3) (or getwd(3)) functions
in Perl.

The abs_path() function takes a single argument and returns the
absolute pathname for that argument.  It uses the same algorithm
as getcwd().  (Actually, getcwd() is abs_path("."))  Symbolic links
and relative-path components ("." and "..") are resolved to return
the canonical pathname, just like realpath(3).  Also callable as
realpath().

The fastcwd() function looks the same as getcwd(), but runs faster.
It's also more dangerous because it might conceivably chdir() you out
of a directory that it can't chdir() you back into.  If fastcwd
encounters a problem it will return undef but will probably leave you
in a different directory.  For a measure of extra security, if
everything appears to have worked, the fastcwd() function will check
that it leaves you in the same directory that it started in. If it has
changed it will C<die> with the message "Unstable directory path,
current directory changed unexpectedly". That should never happen.

The fast_abs_path() function looks the same as abs_path(), but runs faster.
And like fastcwd() is more dangerous.

The cwd() function looks the same as getcwd and fastgetcwd but is
implemented using the most natural and safe form for the current
architecture. For most systems it is identical to `pwd` (but without
the trailing line terminator).

It is recommended that cwd (or another *cwd() function) is used in
I<all> code to ensure portability.

If you ask to override your chdir() built-in function, then your PWD
environment variable will be kept up to date.  (See
L<perlsub/Overriding Builtin Functions>.) Note that it will only be
kept up to date if all packages which use chdir import it from Cwd.

=cut

## use strict;

use Carp;

$VERSION = '2.03';

require Exporter;
@ISA = qw(Exporter);
@EXPORT = qw(cwd getcwd fastcwd fastgetcwd);
@EXPORT_OK = qw(chdir abs_path fast_abs_path realpath fast_realpath);


# The 'natural and safe form' for UNIX (pwd may be setuid root)

sub _backtick_pwd {
    my $cwd;
    chop($cwd = `pwd`);
    $cwd;
}

# Since some ports may predefine cwd internally (e.g., NT)
# we take care not to override an existing definition for cwd().

*cwd = \&_backtick_pwd unless defined &cwd;


# By Brandon S. Allbery
#
# Usage: $cwd = getcwd();

sub getcwd
{
    abs_path('.');
}

# By John Bazik
#
# Usage: $cwd = &fastcwd;
#
# This is a faster version of getcwd.  It's also more dangerous because
# you might chdir out of a directory that you can't chdir back into.
    
sub fastcwd {
    my($odev, $oino, $cdev, $cino, $tdev, $tino);
    my(@path, $path);
    local(*DIR);

    my($orig_cdev, $orig_cino) = stat('.');
    ($cdev, $cino) = ($orig_cdev, $orig_cino);
    for (;;) {
	my $direntry;
	($odev, $oino) = ($cdev, $cino);
	CORE::chdir('..') || return undef;
	($cdev, $cino) = stat('.');
	last if $odev == $cdev && $oino == $cino;
	opendir(DIR, '.') || return undef;
	for (;;) {
	    $direntry = readdir(DIR);
	    last unless defined $direntry;
	    next if $direntry eq '.';
	    next if $direntry eq '..';

	    ($tdev, $tino) = lstat($direntry);
	    last unless $tdev != $odev || $tino != $oino;
	}
	closedir(DIR);
	return undef unless defined $direntry; # should never happen
	unshift(@path, $direntry);
    }
    $path = '/' . join('/', @path);
    if ($^O eq 'apollo') { $path = "/".$path; }
    # At this point $path may be tainted (if tainting) and chdir would fail.
    # To be more useful we untaint it then check that we landed where we started.
    $path = $1 if $path =~ /^(.*)\z/s;	# untaint
    CORE::chdir($path) || return undef;
    ($cdev, $cino) = stat('.');
    die "Unstable directory path, current directory changed unexpectedly"
	if $cdev != $orig_cdev || $cino != $orig_cino;
    $path;
}


# Keeps track of current working directory in PWD environment var
# Usage:
#	use Cwd 'chdir';
#	chdir $newdir;

my $chdir_init = 0;

sub chdir_init {
    if ($ENV{'PWD'} and $^O ne 'os2' and $^O ne 'dos') {
	my($dd,$di) = stat('.');
	my($pd,$pi) = stat($ENV{'PWD'});
	if (!defined $dd or !defined $pd or $di != $pi or $dd != $pd) {
	    $ENV{'PWD'} = cwd();
	}
    }
    else {
	$ENV{'PWD'} = cwd();
    }
    # Strip an automounter prefix (where /tmp_mnt/foo/bar == /foo/bar)
    if ($ENV{'PWD'} =~ m|(/[^/]+(/[^/]+/[^/]+))(.*)|s) {
	my($pd,$pi) = stat($2);
	my($dd,$di) = stat($1);
	if (defined $pd and defined $dd and $di == $pi and $dd == $pd) {
	    $ENV{'PWD'}="$2$3";
	}
    }
    $chdir_init = 1;
}

sub chdir {
    my $newdir = shift || '';	# allow for no arg (chdir to HOME dir)
    $newdir =~ s|///*|/|g;
    chdir_init() unless $chdir_init;
    return 0 unless CORE::chdir $newdir;
    if ($^O eq 'VMS') { return $ENV{'PWD'} = $ENV{'DEFAULT'} }

    if ($newdir =~ m#^/#s) {
	$ENV{'PWD'} = $newdir;
    } else {
	my @curdir = split(m#/#,$ENV{'PWD'});
	@curdir = ('') unless @curdir;
	my $component;
	foreach $component (split(m#/#, $newdir)) {
	    next if $component eq '.';
	    pop(@curdir),next if $component eq '..';
	    push(@curdir,$component);
	}
	$ENV{'PWD'} = join('/',@curdir) || '/';
    }
    1;
}


# By Jeff "japhy" Pinyan (07/23/2000)
#   usage:  abs_path(PATHNAME)
# see the docs

sub abs_path {
  my $base = @_ ? $_[0] : ".";
  my $path = "";
  my $file;

  do {
    my @devino = (stat($base))[0,1] or
      carp("stat($base): $!"), return;

    $base .= "/..";

    opendir PREV, $base or carp("opendir($base): $!"), return;
    while (defined($file = readdir PREV)) {
      next if $file eq "." or $file eq "..";
      my @entry = (lstat("$base/$file"))[0,1] or
        carp("lstat($base/$file): $!"), return;
      last if $devino[0] == $entry[0] and $devino[1] == $entry[1];
    }
    closedir PREV;

    $path = (defined $file and $file) . "/$path";
  } while defined $file;

  length($path) > 1 and chop $path;
  return $path;
}


# added function alias for those of us more
# used to the libc function.  --tchrist 27-Jan-00
*realpath = \&abs_path;

sub fast_abs_path {
    my $cwd = getcwd();
    my $path = shift || '.';
    CORE::chdir($path) || croak "Cannot chdir to $path:$!";
    my $realpath = getcwd();
    CORE::chdir($cwd)  || croak "Cannot chdir back to $cwd:$!";
    $realpath;
}

# added function alias to follow principle of least surprise
# based on previous aliasing.  --tchrist 27-Jan-00
*fast_realpath = \&fast_abs_path;


# --- PORTING SECTION ---

# VMS: $ENV{'DEFAULT'} points to default directory at all times
# 06-Mar-1996  Charles Bailey  bailey@newman.upenn.edu
# Note: Use of Cwd::chdir() causes the logical name PWD to be defined
#   in the process logical name table as the default device and directory
#   seen by Perl. This may not be the same as the default device
#   and directory seen by DCL after Perl exits, since the effects
#   the CRTL chdir() function persist only until Perl exits.

sub _vms_cwd {
    return $ENV{'DEFAULT'};
}

sub _vms_abs_path {
    return $ENV{'DEFAULT'} unless @_;
    my $path = VMS::Filespec::pathify($_[0]);
    croak("Invalid path name $_[0]") unless defined $path;
    return VMS::Filespec::rmsexpand($path);
}

sub _os2_cwd {
    $ENV{'PWD'} = `cmd /c cd`;
    chop $ENV{'PWD'};
    $ENV{'PWD'} =~ s:\\:/:g ;
    return $ENV{'PWD'};
}

sub _win32_cwd {
    $ENV{'PWD'} = Win32::GetCwd();
    $ENV{'PWD'} =~ s:\\:/:g ;
    return $ENV{'PWD'};
}

*_NT_cwd = \&_win32_cwd if (!defined &_NT_cwd && 
                            defined &Win32::GetCwd);

*_NT_cwd = \&_os2_cwd unless defined &_NT_cwd;

sub _dos_cwd {
    if (!defined &Dos::GetCwd) {
        $ENV{'PWD'} = `command /c cd`;
        chop $ENV{'PWD'};
        $ENV{'PWD'} =~ s:\\:/:g ;
    } else {
        $ENV{'PWD'} = Dos::GetCwd();
    }
    return $ENV{'PWD'};
}

sub _qnx_cwd {
    $ENV{'PWD'} = `/usr/bin/fullpath -t`;
    chop $ENV{'PWD'};
    return $ENV{'PWD'};
}

sub _qnx_abs_path {
    my $path = shift || '.';
    my $realpath=`/usr/bin/fullpath -t $path`;
    chop $realpath;
    return $realpath;
}

{
    no warnings;	# assignments trigger 'subroutine redefined' warning

    if ($^O eq 'VMS') {
        *cwd		= \&_vms_cwd;
        *getcwd		= \&_vms_cwd;
        *fastcwd	= \&_vms_cwd;
        *fastgetcwd	= \&_vms_cwd;
        *abs_path	= \&_vms_abs_path;
        *fast_abs_path	= \&_vms_abs_path;
    }
    elsif ($^O eq 'NT' or $^O eq 'MSWin32') {
        # We assume that &_NT_cwd is defined as an XSUB or in the core.
        *cwd		= \&_NT_cwd;
        *getcwd		= \&_NT_cwd;
        *fastcwd	= \&_NT_cwd;
        *fastgetcwd	= \&_NT_cwd;
        *abs_path	= \&fast_abs_path;
    }
    elsif ($^O eq 'os2') {
        # sys_cwd may keep the builtin command
        *cwd		= defined &sys_cwd ? \&sys_cwd : \&_os2_cwd;
        *getcwd		= \&cwd;
        *fastgetcwd	= \&cwd;
        *fastcwd	= \&cwd;
        *abs_path	= \&fast_abs_path;
    }
    elsif ($^O eq 'dos') {
        *cwd		= \&_dos_cwd;
        *getcwd		= \&_dos_cwd;
        *fastgetcwd	= \&_dos_cwd;
        *fastcwd	= \&_dos_cwd;
        *abs_path	= \&fast_abs_path;
    }
    elsif ($^O eq 'qnx') {
        *cwd		= \&_qnx_cwd;
        *getcwd		= \&_qnx_cwd;
        *fastgetcwd	= \&_qnx_cwd;
        *fastcwd	= \&_qnx_cwd;
        *abs_path	= \&_qnx_abs_path;
        *fast_abs_path	= \&_qnx_abs_path;
    }
    elsif ($^O eq 'cygwin') {
        *getcwd	= \&cwd;
        *fastgetcwd	= \&cwd;
        *fastcwd	= \&cwd;
        *abs_path	= \&fast_abs_path;
    }
}

# package main; eval join('',<DATA>) || die $@;	# quick test

1;

__END__
BEGIN { import Cwd qw(:DEFAULT chdir); }
print join("\n", cwd, getcwd, fastcwd, "");
chdir('..');
print join("\n", cwd, getcwd, fastcwd, "");
print "$ENV{PWD}\n";
Commit	Line	Data
a0d0e21e	1	package Cwd;
a0d0e21e	2	require 5.000;
a0d0e21e	3
f06db76b	4	=head1 NAME
	5
	6	getcwd - get pathname of current working directory
	7
	8	=head1 SYNOPSIS
	9
4633a7c4	10	use Cwd;
	11	$dir = cwd;
	12
	13	use Cwd;
	14	$dir = getcwd;
f06db76b	15
f06db76b	16	use Cwd;
4633a7c4	17	$dir = fastgetcwd;
f06db76b	18
	19	use Cwd 'chdir';
	20	chdir "/tmp";
	21	print $ENV{'PWD'};
	22
e4c51978	23	use Cwd 'abs_path'; # aka realpath()
20408e3c	24	print abs_path($ENV{'PWD'});
	25
	26	use Cwd 'fast_abs_path';
	27	print fast_abs_path($ENV{'PWD'});
	28
f06db76b	29	=head1 DESCRIPTION
	30
	31	The getcwd() function re-implements the getcwd(3) (or getwd(3)) functions
4633a7c4	32	in Perl.
f06db76b	33
20408e3c	34	The abs_path() function takes a single argument and returns the
e4c51978	35	absolute pathname for that argument. It uses the same algorithm
	36	as getcwd(). (Actually, getcwd() is abs_path(".")) Symbolic links
	37	and relative-path components ("." and "..") are resolved to return
	38	the canonical pathname, just like realpath(3). Also callable as
	39	realpath().
20408e3c	40
cb1a09d0	41	The fastcwd() function looks the same as getcwd(), but runs faster.
fb73857a	42	It's also more dangerous because it might conceivably chdir() you out
	43	of a directory that it can't chdir() you back into. If fastcwd
	44	encounters a problem it will return undef but will probably leave you
	45	in a different directory. For a measure of extra security, if
	46	everything appears to have worked, the fastcwd() function will check
	47	that it leaves you in the same directory that it started in. If it has
	48	changed it will C<die> with the message "Unstable directory path,
	49	current directory changed unexpectedly". That should never happen.
f06db76b	50
20408e3c	51	The fast_abs_path() function looks the same as abs_path(), but runs faster.
	52	And like fastcwd() is more dangerous.
	53
4633a7c4	54	The cwd() function looks the same as getcwd and fastgetcwd but is
	55	implemented using the most natural and safe form for the current
	56	architecture. For most systems it is identical to `pwd` (but without
fb73857a	57	the trailing line terminator).
	58
	59	It is recommended that cwd (or another *cwd() function) is used in
	60	I<all> code to ensure portability.
4633a7c4	61
	62	If you ask to override your chdir() built-in function, then your PWD
	63	environment variable will be kept up to date. (See
55497cff	64	L<perlsub/Overriding Builtin Functions>.) Note that it will only be
1fef88e7	65	kept up to date if all packages which use chdir import it from Cwd.
4633a7c4	66
f06db76b	67	=cut
f06db76b	68
96e4d5b1	69	## use strict;
	70
	71	use Carp;
	72
929327b2	73	$VERSION = '2.03';
96e4d5b1	74
96e4d5b1	75	require Exporter;
a0d0e21e	76	@ISA = qw(Exporter);
e7ae0116	77	@EXPORT = qw(cwd getcwd fastcwd fastgetcwd);
e4c51978	78	@EXPORT_OK = qw(chdir abs_path fast_abs_path realpath fast_realpath);
a0d0e21e	79
4633a7c4	80
8b88ae92	81	# The 'natural and safe form' for UNIX (pwd may be setuid root)
96e4d5b1	82
8b88ae92	83	sub _backtick_pwd {
4633a7c4	84	my $cwd;
	85	chop($cwd = `pwd`);
	86	$cwd;
8b88ae92	87	}
4633a7c4	88
	89	# Since some ports may predefine cwd internally (e.g., NT)
	90	# we take care not to override an existing definition for cwd().
	91
	92	*cwd = \&_backtick_pwd unless defined &cwd;
a0d0e21e	93
748a9306	94
a0d0e21e	95	# By Brandon S. Allbery
	96	#
	97	# Usage: $cwd = getcwd();
	98
	99	sub getcwd
	100	{
07569ed3	101	abs_path('.');
a0d0e21e	102	}
a0d0e21e	103
a0d0e21e	104	# By John Bazik
	105	#
	106	# Usage: $cwd = &fastcwd;
	107	#
	108	# This is a faster version of getcwd. It's also more dangerous because
	109	# you might chdir out of a directory that you can't chdir back into.
fb73857a	110
a0d0e21e	111	sub fastcwd {
	112	my($odev, $oino, $cdev, $cino, $tdev, $tino);
	113	my(@path, $path);
	114	local(*DIR);
	115
fb73857a	116	my($orig_cdev, $orig_cino) = stat('.');
fb73857a	117	($cdev, $cino) = ($orig_cdev, $orig_cino);
a0d0e21e	118	for (;;) {
40000a8c	119	my $direntry;
a0d0e21e	120	($odev, $oino) = ($cdev, $cino);
e79e61e4	121	CORE::chdir('..') \|\| return undef;
a0d0e21e	122	($cdev, $cino) = stat('.');
a0d0e21e	123	last if $odev == $cdev && $oino == $cino;
fb73857a	124	opendir(DIR, '.') \|\| return undef;
a0d0e21e	125	for (;;) {
40000a8c	126	$direntry = readdir(DIR);
fb73857a	127	last unless defined $direntry;
40000a8c	128	next if $direntry eq '.';
40000a8c	129	next if $direntry eq '..';
a0d0e21e	130
40000a8c	131	($tdev, $tino) = lstat($direntry);
a0d0e21e	132	last unless $tdev != $odev \|\| $tino != $oino;
	133	}
	134	closedir(DIR);
fb73857a	135	return undef unless defined $direntry; # should never happen
40000a8c	136	unshift(@path, $direntry);
a0d0e21e	137	}
fb73857a	138	$path = '/' . join('/', @path);
21ac5ced	139	if ($^O eq 'apollo') { $path = "/".$path; }
fb73857a	140	# At this point $path may be tainted (if tainting) and chdir would fail.
fb73857a	141	# To be more useful we untaint it then check that we landed where we started.
392d8ab8	142	$path = $1 if $path =~ /^(.*)\z/s; # untaint
e79e61e4	143	CORE::chdir($path) \|\| return undef;
fb73857a	144	($cdev, $cino) = stat('.');
	145	die "Unstable directory path, current directory changed unexpectedly"
	146	if $cdev != $orig_cdev \|\| $cino != $orig_cino;
a0d0e21e	147	$path;
	148	}
	149
	150
4633a7c4	151	# Keeps track of current working directory in PWD environment var
a0d0e21e	152	# Usage:
	153	# use Cwd 'chdir';
	154	# chdir $newdir;
	155
4633a7c4	156	my $chdir_init = 0;
a0d0e21e	157
4633a7c4	158	sub chdir_init {
39e571d4	159	if ($ENV{'PWD'} and $^O ne 'os2' and $^O ne 'dos') {
a0d0e21e	160	my($dd,$di) = stat('.');
	161	my($pd,$pi) = stat($ENV{'PWD'});
	162	if (!defined $dd or !defined $pd or $di != $pi or $dd != $pd) {
4633a7c4	163	$ENV{'PWD'} = cwd();
a0d0e21e	164	}
	165	}
	166	else {
4633a7c4	167	$ENV{'PWD'} = cwd();
a0d0e21e	168	}
4633a7c4	169	# Strip an automounter prefix (where /tmp_mnt/foo/bar == /foo/bar)
392d8ab8	170	if ($ENV{'PWD'} =~ m\|(/[^/]+(/[^/]+/[^/]+))(.*)\|s) {
a0d0e21e	171	my($pd,$pi) = stat($2);
	172	my($dd,$di) = stat($1);
	173	if (defined $pd and defined $dd and $di == $pi and $dd == $pd) {
	174	$ENV{'PWD'}="$2$3";
	175	}
	176	}
	177	$chdir_init = 1;
	178	}
	179
	180	sub chdir {
4633a7c4	181	my $newdir = shift \|\| ''; # allow for no arg (chdir to HOME dir)
4633a7c4	182	$newdir =~ s\|///*\|/\|g;
a0d0e21e	183	chdir_init() unless $chdir_init;
4633a7c4	184	return 0 unless CORE::chdir $newdir;
c6538b72	185	if ($^O eq 'VMS') { return $ENV{'PWD'} = $ENV{'DEFAULT'} }
748a9306	186
392d8ab8	187	if ($newdir =~ m#^/#s) {
a0d0e21e	188	$ENV{'PWD'} = $newdir;
4633a7c4	189	} else {
	190	my @curdir = split(m#/#,$ENV{'PWD'});
	191	@curdir = ('') unless @curdir;
	192	my $component;
a0d0e21e	193	foreach $component (split(m#/#, $newdir)) {
	194	next if $component eq '.';
	195	pop(@curdir),next if $component eq '..';
	196	push(@curdir,$component);
	197	}
	198	$ENV{'PWD'} = join('/',@curdir) \|\| '/';
	199	}
4633a7c4	200	1;
a0d0e21e	201	}
a0d0e21e	202
8b88ae92	203
929327b2	204	# By Jeff "japhy" Pinyan (07/23/2000)
	205	# usage: abs_path(PATHNAME)
	206	# see the docs
	207
	208	sub abs_path {
	209	my $base = @_ ? $_[0] : ".";
	210	my $path = "";
	211	my $file;
	212
	213	do {
	214	my @devino = (stat($base))[0,1] or
	215	carp("stat($base): $!"), return;
8b88ae92	216
929327b2	217	$base .= "/..";
	218
	219	opendir PREV, $base or carp("opendir($base): $!"), return;
	220	while (defined($file = readdir PREV)) {
	221	next if $file eq "." or $file eq "..";
	222	my @entry = (lstat("$base/$file"))[0,1] or
	223	carp("lstat($base/$file): $!"), return;
	224	last if $devino[0] == $entry[0] and $devino[1] == $entry[1];
8b88ae92	225	}
929327b2	226	closedir PREV;
	227
	228	$path = (defined $file and $file) . "/$path";
	229	} while defined $file;
	230
	231	length($path) > 1 and chop $path;
	232	return $path;
8b88ae92	233	}
8b88ae92	234
929327b2	235
e4c51978	236	# added function alias for those of us more
	237	# used to the libc function. --tchrist 27-Jan-00
	238	*realpath = \&abs_path;
	239
96e4d5b1	240	sub fast_abs_path {
	241	my $cwd = getcwd();
	242	my $path = shift \|\| '.';
e79e61e4	243	CORE::chdir($path) \|\| croak "Cannot chdir to $path:$!";
96e4d5b1	244	my $realpath = getcwd();
e79e61e4	245	CORE::chdir($cwd) \|\| croak "Cannot chdir back to $cwd:$!";
96e4d5b1	246	$realpath;
8b88ae92	247	}
8b88ae92	248
e4c51978	249	# added function alias to follow principle of least surprise
	250	# based on previous aliasing. --tchrist 27-Jan-00
	251	*fast_realpath = \&fast_abs_path;
	252
4633a7c4	253
	254	# --- PORTING SECTION ---
	255
	256	# VMS: $ENV{'DEFAULT'} points to default directory at all times
bd3fa61c	257	# 06-Mar-1996 Charles Bailey bailey@newman.upenn.edu
c6538b72	258	# Note: Use of Cwd::chdir() causes the logical name PWD to be defined
8b88ae92	259	# in the process logical name table as the default device and directory
8b88ae92	260	# seen by Perl. This may not be the same as the default device
4633a7c4	261	# and directory seen by DCL after Perl exits, since the effects
4633a7c4	262	# the CRTL chdir() function persist only until Perl exits.
4633a7c4	263
4633a7c4	264	sub _vms_cwd {
96e4d5b1	265	return $ENV{'DEFAULT'};
	266	}
	267
	268	sub _vms_abs_path {
	269	return $ENV{'DEFAULT'} unless @_;
	270	my $path = VMS::Filespec::pathify($_[0]);
	271	croak("Invalid path name $_[0]") unless defined $path;
	272	return VMS::Filespec::rmsexpand($path);
4633a7c4	273	}
68dc0745	274
4633a7c4	275	sub _os2_cwd {
	276	$ENV{'PWD'} = `cmd /c cd`;
	277	chop $ENV{'PWD'};
	278	$ENV{'PWD'} =~ s:\\:/:g ;
	279	return $ENV{'PWD'};
	280	}
	281
96e4d5b1	282	sub _win32_cwd {
2d7a9237	283	$ENV{'PWD'} = Win32::GetCwd();
96e4d5b1	284	$ENV{'PWD'} =~ s:\\:/:g ;
	285	return $ENV{'PWD'};
	286	}
	287
	288	*_NT_cwd = \&_win32_cwd if (!defined &_NT_cwd &&
2d7a9237	289	defined &Win32::GetCwd);
96e4d5b1	290
96e4d5b1	291	*_NT_cwd = \&_os2_cwd unless defined &_NT_cwd;
68dc0745	292
39e571d4	293	sub _dos_cwd {
	294	if (!defined &Dos::GetCwd) {
	295	$ENV{'PWD'} = `command /c cd`;
	296	chop $ENV{'PWD'};
	297	$ENV{'PWD'} =~ s:\\:/:g ;
	298	} else {
	299	$ENV{'PWD'} = Dos::GetCwd();
	300	}
55497cff	301	return $ENV{'PWD'};
	302	}
	303
7fbf1995	304	sub _qnx_cwd {
	305	$ENV{'PWD'} = `/usr/bin/fullpath -t`;
	306	chop $ENV{'PWD'};
	307	return $ENV{'PWD'};
	308	}
	309
	310	sub _qnx_abs_path {
	311	my $path = shift \|\| '.';
	312	my $realpath=`/usr/bin/fullpath -t $path`;
	313	chop $realpath;
	314	return $realpath;
	315	}
	316
ac1ad7f0	317	{
db376a24	318	no warnings; # assignments trigger 'subroutine redefined' warning
4633a7c4	319
ac1ad7f0	320	if ($^O eq 'VMS') {
96e4d5b1	321	*cwd = \&_vms_cwd;
	322	*getcwd = \&_vms_cwd;
	323	*fastcwd = \&_vms_cwd;
	324	*fastgetcwd = \&_vms_cwd;
	325	*abs_path = \&_vms_abs_path;
	326	*fast_abs_path = \&_vms_abs_path;
ac1ad7f0	327	}
	328	elsif ($^O eq 'NT' or $^O eq 'MSWin32') {
	329	# We assume that &_NT_cwd is defined as an XSUB or in the core.
96e4d5b1	330	*cwd = \&_NT_cwd;
	331	*getcwd = \&_NT_cwd;
	332	*fastcwd = \&_NT_cwd;
	333	*fastgetcwd = \&_NT_cwd;
	334	*abs_path = \&fast_abs_path;
ac1ad7f0	335	}
	336	elsif ($^O eq 'os2') {
	337	# sys_cwd may keep the builtin command
96e4d5b1	338	*cwd = defined &sys_cwd ? \&sys_cwd : \&_os2_cwd;
	339	*getcwd = \&cwd;
	340	*fastgetcwd = \&cwd;
	341	*fastcwd = \&cwd;
	342	*abs_path = \&fast_abs_path;
ac1ad7f0	343	}
39e571d4	344	elsif ($^O eq 'dos') {
	345	*cwd = \&_dos_cwd;
	346	*getcwd = \&_dos_cwd;
	347	*fastgetcwd = \&_dos_cwd;
	348	*fastcwd = \&_dos_cwd;
96e4d5b1	349	*abs_path = \&fast_abs_path;
ac1ad7f0	350	}
7fbf1995	351	elsif ($^O eq 'qnx') {
	352	*cwd = \&_qnx_cwd;
	353	*getcwd = \&_qnx_cwd;
	354	*fastgetcwd = \&_qnx_cwd;
	355	*fastcwd = \&_qnx_cwd;
	356	*abs_path = \&_qnx_abs_path;
	357	*fast_abs_path = \&_qnx_abs_path;
	358	}
4fabb596	359	elsif ($^O eq 'cygwin') {
1cab015a	360	*getcwd = \&cwd;
	361	*fastgetcwd = \&cwd;
	362	*fastcwd = \&cwd;
	363	*abs_path = \&fast_abs_path;
	364	}
55497cff	365	}
4633a7c4	366
	367	# package main; eval join('',<DATA>) \|\| die $@; # quick test
	368
a0d0e21e	369	1;
a0d0e21e	370
4633a7c4	371	__END__
	372	BEGIN { import Cwd qw(:DEFAULT chdir); }
	373	print join("\n", cwd, getcwd, fastcwd, "");
	374	chdir('..');
	375	print join("\n", cwd, getcwd, fastcwd, "");
	376	print "$ENV{PWD}\n";