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1 | package Cwd; |
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2 | require 5.6.0; |
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3 | |
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4 | =head1 NAME |
5 | |
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6 | Cwd - get pathname of current working directory |
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7 | |
8 | =head1 SYNOPSIS |
9 | |
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10 | use Cwd; |
11 | $dir = cwd; |
12 | |
13 | use Cwd; |
14 | $dir = getcwd; |
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15 | |
16 | use Cwd; |
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17 | $dir = fastcwd; |
18 | |
19 | use Cwd; |
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20 | $dir = fastgetcwd; |
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21 | |
22 | use Cwd 'chdir'; |
23 | chdir "/tmp"; |
24 | print $ENV{'PWD'}; |
25 | |
e4c51978 |
26 | use Cwd 'abs_path'; # aka realpath() |
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27 | print abs_path($ENV{'PWD'}); |
28 | |
29 | use Cwd 'fast_abs_path'; |
30 | print fast_abs_path($ENV{'PWD'}); |
31 | |
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32 | =head1 DESCRIPTION |
33 | |
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34 | This module provides functions for determining the pathname of the |
35 | current working directory. By default, it exports the functions |
36 | cwd(), getcwd(), fastcwd(), and fastgetcwd() into the caller's |
37 | namespace. Each of these functions are called without arguments and |
38 | return the absolute path of the current working directory. It is |
39 | recommended that cwd (or another *cwd() function) be used in I<all> |
40 | code to ensure portability. |
41 | |
42 | The cwd() is the most natural and safe form for the current |
43 | architecture. For most systems it is identical to `pwd` (but without |
44 | the trailing line terminator). |
45 | |
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46 | The getcwd() function re-implements the getcwd(3) (or getwd(3)) functions |
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47 | in Perl. |
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48 | |
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49 | The fastcwd() function looks the same as getcwd(), but runs faster. |
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50 | It's also more dangerous because it might conceivably chdir() you out |
51 | of a directory that it can't chdir() you back into. If fastcwd |
52 | encounters a problem it will return undef but will probably leave you |
53 | in a different directory. For a measure of extra security, if |
54 | everything appears to have worked, the fastcwd() function will check |
55 | that it leaves you in the same directory that it started in. If it has |
56 | changed it will C<die> with the message "Unstable directory path, |
57 | current directory changed unexpectedly". That should never happen. |
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58 | |
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59 | The fastgetcwd() function is provided as a synonym for cwd(). |
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60 | |
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61 | The abs_path() function takes a single argument and returns the |
62 | absolute pathname for that argument. It uses the same algorithm as |
63 | getcwd(). (Actually, getcwd() is abs_path(".")) Symbolic links and |
64 | relative-path components ("." and "..") are resolved to return the |
65 | canonical pathname, just like realpath(3). This function is also |
66 | callable as realpath(). |
67 | |
68 | The fast_abs_path() function looks the same as abs_path() but runs |
69 | faster and, like fastcwd(), is more dangerous. |
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70 | |
71 | If you ask to override your chdir() built-in function, then your PWD |
72 | environment variable will be kept up to date. (See |
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73 | L<perlsub/Overriding Builtin Functions>.) Note that it will only be |
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74 | kept up to date if all packages which use chdir import it from Cwd. |
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75 | |
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76 | =head1 NOTES |
77 | |
78 | =over 4 |
79 | |
80 | =item * |
81 | |
82 | On Mac OS (Classic), the path separator is ':', not '/', and the |
83 | current directory is denoted as ':', not '.'. To move up the directory |
84 | tree, you will use '::' to move up one level, but ':::' and so on to |
85 | move up the tree two or more levels (i.e. the equivalent to '../../..' |
86 | is '::::'). Generally, you should be careful about specifying relative pathnames. |
87 | While a full path always begins with a volume name, a relative pathname |
88 | should always begin with a ':'. If specifying a volume name only, a |
89 | trailing ':' is required. |
90 | |
91 | Actually, on Mac OS, the C<getcwd()>, C<fastgetcwd()> and C<fastcwd()> |
92 | functions are all aliases for the C<cwd()> function, which, on Mac OS, |
93 | calls `pwd`. Likewise, the C<abs_path()> function is an alias for |
94 | C<fast_abs_path()>. |
95 | |
96 | =back |
97 | |
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98 | =cut |
99 | |
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100 | use strict; |
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101 | |
102 | use Carp; |
103 | |
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104 | our $VERSION = '2.05'; |
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105 | |
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106 | use base qw/ Exporter /; |
107 | our @EXPORT = qw(cwd getcwd fastcwd fastgetcwd); |
108 | our @EXPORT_OK = qw(chdir abs_path fast_abs_path realpath fast_realpath); |
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109 | |
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110 | # sys_cwd may keep the builtin command |
111 | |
112 | # All the functionality of this module may provided by builtins, |
113 | # there is no sense to process the rest of the file. |
114 | # The best choice may be to have this in BEGIN, but how to return from BEGIN? |
115 | |
116 | if ($^O eq 'os2' && defined &sys_cwd && defined &sys_abspath) { |
117 | local $^W = 0; |
118 | *cwd = \&sys_cwd; |
119 | *getcwd = \&cwd; |
120 | *fastgetcwd = \&cwd; |
121 | *fastcwd = \&cwd; |
122 | *abs_path = \&sys_abspath; |
123 | *fast_abs_path = \&abs_path; |
124 | *realpath = \&abs_path; |
125 | *fast_realpath = \&abs_path; |
126 | return 1; |
127 | } |
128 | |
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129 | eval { |
130 | require XSLoader; |
131 | XSLoader::load('Cwd'); |
132 | }; |
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133 | |
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134 | # The 'natural and safe form' for UNIX (pwd may be setuid root) |
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135 | |
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136 | sub _backtick_pwd { |
7e03f963 |
137 | my $cwd = `pwd`; |
138 | # `pwd` may fail e.g. if the disk is full |
139 | chomp($cwd) if defined $cwd; |
4633a7c4 |
140 | $cwd; |
8b88ae92 |
141 | } |
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142 | |
143 | # Since some ports may predefine cwd internally (e.g., NT) |
144 | # we take care not to override an existing definition for cwd(). |
145 | |
ea54c8bd |
146 | unless(defined &cwd) { |
147 | # The pwd command is not available in some chroot(2)'ed environments |
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148 | if($^O eq 'MacOS' || grep { -x "$_/pwd" } split(':', $ENV{PATH})) { |
ea54c8bd |
149 | *cwd = \&_backtick_pwd; |
150 | } |
151 | else { |
152 | *cwd = \&getcwd; |
153 | } |
154 | } |
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155 | |
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156 | # set a reasonable (and very safe) default for fastgetcwd, in case it |
157 | # isn't redefined later (20001212 rspier) |
158 | *fastgetcwd = \&cwd; |
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159 | |
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160 | # By Brandon S. Allbery |
161 | # |
162 | # Usage: $cwd = getcwd(); |
163 | |
164 | sub getcwd |
165 | { |
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166 | abs_path('.'); |
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167 | } |
168 | |
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169 | # Keeps track of current working directory in PWD environment var |
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170 | # Usage: |
171 | # use Cwd 'chdir'; |
172 | # chdir $newdir; |
173 | |
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174 | my $chdir_init = 0; |
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175 | |
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176 | sub chdir_init { |
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177 | if ($ENV{'PWD'} and $^O ne 'os2' and $^O ne 'dos' and $^O ne 'MSWin32') { |
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178 | my($dd,$di) = stat('.'); |
179 | my($pd,$pi) = stat($ENV{'PWD'}); |
180 | if (!defined $dd or !defined $pd or $di != $pi or $dd != $pd) { |
4633a7c4 |
181 | $ENV{'PWD'} = cwd(); |
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182 | } |
183 | } |
184 | else { |
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185 | my $wd = cwd(); |
186 | $wd = Win32::GetFullPathName($wd) if $^O eq 'MSWin32'; |
187 | $ENV{'PWD'} = $wd; |
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188 | } |
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189 | # Strip an automounter prefix (where /tmp_mnt/foo/bar == /foo/bar) |
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190 | if ($^O ne 'MSWin32' and $ENV{'PWD'} =~ m|(/[^/]+(/[^/]+/[^/]+))(.*)|s) { |
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191 | my($pd,$pi) = stat($2); |
192 | my($dd,$di) = stat($1); |
193 | if (defined $pd and defined $dd and $di == $pi and $dd == $pd) { |
194 | $ENV{'PWD'}="$2$3"; |
195 | } |
196 | } |
197 | $chdir_init = 1; |
198 | } |
199 | |
200 | sub chdir { |
22978713 |
201 | my $newdir = @_ ? shift : ''; # allow for no arg (chdir to HOME dir) |
3b8e3443 |
202 | $newdir =~ s|///*|/|g unless $^O eq 'MSWin32'; |
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203 | chdir_init() unless $chdir_init; |
4ffa1610 |
204 | my $newpwd; |
205 | if ($^O eq 'MSWin32') { |
206 | # get the full path name *before* the chdir() |
207 | $newpwd = Win32::GetFullPathName($newdir); |
208 | } |
209 | |
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210 | return 0 unless CORE::chdir $newdir; |
4ffa1610 |
211 | |
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212 | if ($^O eq 'VMS') { |
213 | return $ENV{'PWD'} = $ENV{'DEFAULT'} |
214 | } |
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215 | elsif ($^O eq 'MacOS') { |
216 | return $ENV{'PWD'} = cwd(); |
217 | } |
3b8e3443 |
218 | elsif ($^O eq 'MSWin32') { |
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219 | $ENV{'PWD'} = $newpwd; |
3b8e3443 |
220 | return 1; |
221 | } |
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222 | |
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223 | if ($newdir =~ m#^/#s) { |
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224 | $ENV{'PWD'} = $newdir; |
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225 | } else { |
226 | my @curdir = split(m#/#,$ENV{'PWD'}); |
227 | @curdir = ('') unless @curdir; |
228 | my $component; |
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229 | foreach $component (split(m#/#, $newdir)) { |
230 | next if $component eq '.'; |
231 | pop(@curdir),next if $component eq '..'; |
232 | push(@curdir,$component); |
233 | } |
234 | $ENV{'PWD'} = join('/',@curdir) || '/'; |
235 | } |
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236 | 1; |
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237 | } |
238 | |
e4c51978 |
239 | # added function alias for those of us more |
240 | # used to the libc function. --tchrist 27-Jan-00 |
241 | *realpath = \&abs_path; |
242 | |
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243 | sub fast_abs_path { |
244 | my $cwd = getcwd(); |
4d6b4052 |
245 | require File::Spec; |
246 | my $path = @_ ? shift : File::Spec->curdir; |
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247 | CORE::chdir($path) || croak "Cannot chdir to $path:$!"; |
96e4d5b1 |
248 | my $realpath = getcwd(); |
e79e61e4 |
249 | CORE::chdir($cwd) || croak "Cannot chdir back to $cwd:$!"; |
96e4d5b1 |
250 | $realpath; |
8b88ae92 |
251 | } |
252 | |
e4c51978 |
253 | # added function alias to follow principle of least surprise |
254 | # based on previous aliasing. --tchrist 27-Jan-00 |
255 | *fast_realpath = \&fast_abs_path; |
256 | |
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257 | |
258 | # --- PORTING SECTION --- |
259 | |
260 | # VMS: $ENV{'DEFAULT'} points to default directory at all times |
bd3fa61c |
261 | # 06-Mar-1996 Charles Bailey bailey@newman.upenn.edu |
c6538b72 |
262 | # Note: Use of Cwd::chdir() causes the logical name PWD to be defined |
8b88ae92 |
263 | # in the process logical name table as the default device and directory |
264 | # seen by Perl. This may not be the same as the default device |
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265 | # and directory seen by DCL after Perl exits, since the effects |
266 | # the CRTL chdir() function persist only until Perl exits. |
4633a7c4 |
267 | |
268 | sub _vms_cwd { |
96e4d5b1 |
269 | return $ENV{'DEFAULT'}; |
270 | } |
271 | |
272 | sub _vms_abs_path { |
273 | return $ENV{'DEFAULT'} unless @_; |
274 | my $path = VMS::Filespec::pathify($_[0]); |
275 | croak("Invalid path name $_[0]") unless defined $path; |
276 | return VMS::Filespec::rmsexpand($path); |
4633a7c4 |
277 | } |
68dc0745 |
278 | |
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279 | sub _os2_cwd { |
280 | $ENV{'PWD'} = `cmd /c cd`; |
281 | chop $ENV{'PWD'}; |
282 | $ENV{'PWD'} =~ s:\\:/:g ; |
283 | return $ENV{'PWD'}; |
284 | } |
285 | |
96e4d5b1 |
286 | sub _win32_cwd { |
2d7a9237 |
287 | $ENV{'PWD'} = Win32::GetCwd(); |
96e4d5b1 |
288 | $ENV{'PWD'} =~ s:\\:/:g ; |
289 | return $ENV{'PWD'}; |
290 | } |
291 | |
292 | *_NT_cwd = \&_win32_cwd if (!defined &_NT_cwd && |
2d7a9237 |
293 | defined &Win32::GetCwd); |
96e4d5b1 |
294 | |
295 | *_NT_cwd = \&_os2_cwd unless defined &_NT_cwd; |
68dc0745 |
296 | |
39e571d4 |
297 | sub _dos_cwd { |
298 | if (!defined &Dos::GetCwd) { |
299 | $ENV{'PWD'} = `command /c cd`; |
300 | chop $ENV{'PWD'}; |
301 | $ENV{'PWD'} =~ s:\\:/:g ; |
302 | } else { |
303 | $ENV{'PWD'} = Dos::GetCwd(); |
304 | } |
55497cff |
305 | return $ENV{'PWD'}; |
306 | } |
307 | |
7fbf1995 |
308 | sub _qnx_cwd { |
309 | $ENV{'PWD'} = `/usr/bin/fullpath -t`; |
310 | chop $ENV{'PWD'}; |
311 | return $ENV{'PWD'}; |
312 | } |
313 | |
314 | sub _qnx_abs_path { |
fa921dc6 |
315 | my $path = @_ ? shift : '.'; |
7fbf1995 |
316 | my $realpath=`/usr/bin/fullpath -t $path`; |
317 | chop $realpath; |
318 | return $realpath; |
319 | } |
320 | |
ed79a026 |
321 | sub _epoc_cwd { |
322 | $ENV{'PWD'} = EPOC::getcwd(); |
323 | return $ENV{'PWD'}; |
324 | } |
325 | |
ac1ad7f0 |
326 | { |
db376a24 |
327 | no warnings; # assignments trigger 'subroutine redefined' warning |
4633a7c4 |
328 | |
ac1ad7f0 |
329 | if ($^O eq 'VMS') { |
96e4d5b1 |
330 | *cwd = \&_vms_cwd; |
331 | *getcwd = \&_vms_cwd; |
332 | *fastcwd = \&_vms_cwd; |
333 | *fastgetcwd = \&_vms_cwd; |
334 | *abs_path = \&_vms_abs_path; |
335 | *fast_abs_path = \&_vms_abs_path; |
ac1ad7f0 |
336 | } |
337 | elsif ($^O eq 'NT' or $^O eq 'MSWin32') { |
338 | # We assume that &_NT_cwd is defined as an XSUB or in the core. |
96e4d5b1 |
339 | *cwd = \&_NT_cwd; |
340 | *getcwd = \&_NT_cwd; |
341 | *fastcwd = \&_NT_cwd; |
342 | *fastgetcwd = \&_NT_cwd; |
343 | *abs_path = \&fast_abs_path; |
ac1ad7f0 |
344 | } |
345 | elsif ($^O eq 'os2') { |
346 | # sys_cwd may keep the builtin command |
96e4d5b1 |
347 | *cwd = defined &sys_cwd ? \&sys_cwd : \&_os2_cwd; |
348 | *getcwd = \&cwd; |
349 | *fastgetcwd = \&cwd; |
350 | *fastcwd = \&cwd; |
351 | *abs_path = \&fast_abs_path; |
ac1ad7f0 |
352 | } |
39e571d4 |
353 | elsif ($^O eq 'dos') { |
354 | *cwd = \&_dos_cwd; |
355 | *getcwd = \&_dos_cwd; |
356 | *fastgetcwd = \&_dos_cwd; |
357 | *fastcwd = \&_dos_cwd; |
96e4d5b1 |
358 | *abs_path = \&fast_abs_path; |
ac1ad7f0 |
359 | } |
7438b6ad |
360 | elsif ($^O =~ m/^(?:qnx|nto)$/ ) { |
7fbf1995 |
361 | *cwd = \&_qnx_cwd; |
362 | *getcwd = \&_qnx_cwd; |
363 | *fastgetcwd = \&_qnx_cwd; |
364 | *fastcwd = \&_qnx_cwd; |
365 | *abs_path = \&_qnx_abs_path; |
366 | *fast_abs_path = \&_qnx_abs_path; |
367 | } |
4fabb596 |
368 | elsif ($^O eq 'cygwin') { |
1cab015a |
369 | *getcwd = \&cwd; |
370 | *fastgetcwd = \&cwd; |
371 | *fastcwd = \&cwd; |
372 | *abs_path = \&fast_abs_path; |
373 | } |
ed79a026 |
374 | elsif ($^O eq 'epoc') { |
fa6a1c44 |
375 | *cwd = \&_epoc_cwd; |
376 | *getcwd = \&_epoc_cwd; |
ed79a026 |
377 | *fastgetcwd = \&_epoc_cwd; |
378 | *fastcwd = \&_epoc_cwd; |
379 | *abs_path = \&fast_abs_path; |
380 | } |
4aecb5b5 |
381 | elsif ($^O eq 'MacOS') { |
382 | *getcwd = \&cwd; |
383 | *fastgetcwd = \&cwd; |
384 | *fastcwd = \&cwd; |
385 | *abs_path = \&fast_abs_path; |
386 | } |
55497cff |
387 | } |
4633a7c4 |
388 | |
389 | # package main; eval join('',<DATA>) || die $@; # quick test |
390 | |
a0d0e21e |
391 | 1; |
392 | |
4633a7c4 |
393 | __END__ |
394 | BEGIN { import Cwd qw(:DEFAULT chdir); } |
395 | print join("\n", cwd, getcwd, fastcwd, ""); |
396 | chdir('..'); |
397 | print join("\n", cwd, getcwd, fastcwd, ""); |
398 | print "$ENV{PWD}\n"; |