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VMS-specific tweak to FindBin for when $0 returns a unix-style filespec.
[perl5.git] / lib / FindBin.pm
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1# FindBin.pm
2#
3# Copyright (c) 1995 Graham Barr & Nick Ing-Simmons. All rights reserved.
4# This program is free software; you can redistribute it and/or modify it
5# under the same terms as Perl itself.
6
7=head1 NAME
8
9FindBin - Locate directory of original perl script
10
11=head1 SYNOPSIS
12
13 use FindBin;
d7791a84 14 use lib "$FindBin::Bin/../lib";
a73990fd 15
8b88ae92 16 or
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17
18 use FindBin qw($Bin);
d7791a84 19 use lib "$Bin/../lib";
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20
21=head1 DESCRIPTION
22
23Locates the full path to the script bin directory to allow the use
24of paths relative to the bin directory.
25
26This allows a user to setup a directory tree for some software with
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27directories C<< <root>/bin >> and C<< <root>/lib >>, and then the above
28example will allow the use of modules in the lib directory without knowing
29where the software tree is installed.
a73990fd 30
84dc3c4d 31If perl is invoked using the B<-e> option or the perl script is read from
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32C<STDIN> then FindBin sets both C<$Bin> and C<$RealBin> to the current
33directory.
34
35=head1 EXPORTABLE VARIABLES
36
37 $Bin - path to bin directory from where script was invoked
38 $Script - basename of script from which perl was invoked
39 $RealBin - $Bin with all links resolved
40 $RealScript - $Script with all links resolved
41
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42=head1 KNOWN ISSUES
43
44If there are two modules using C<FindBin> from different directories
f5094128 45under the same interpreter, this won't work. Since C<FindBin> uses a
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46C<BEGIN> block, it'll be executed only once, and only the first caller
47will get it right. This is a problem under mod_perl and other persistent
48Perl environments, where you shouldn't use this module. Which also means
49that you should avoid using C<FindBin> in modules that you plan to put
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50on CPAN. To make sure that C<FindBin> will work is to call the C<again>
51function:
52
53 use FindBin;
54 FindBin::again(); # or FindBin->again;
55
56In former versions of FindBin there was no C<again> function. The
57workaround was to force the C<BEGIN> block to be executed again:
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58
59 delete $INC{'FindBin.pm'};
60 require FindBin;
61
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62=head1 KNOWN BUGS
63
11cd4567 64If perl is invoked as
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65
66 perl filename
67
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68and I<filename> does not have executable rights and a program called
69I<filename> exists in the users C<$ENV{PATH}> which satisfies both B<-x>
70and B<-T> then FindBin assumes that it was invoked via the
71C<$ENV{PATH}>.
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72
73Workaround is to invoke perl as
74
75 perl ./filename
76
77=head1 AUTHORS
78
d250f4d1 79FindBin is supported as part of the core perl distribution. Please send bug
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80reports to E<lt>F<perlbug@perl.org>E<gt> using the perlbug program
81included with perl.
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82
83Graham Barr E<lt>F<gbarr@pobox.com>E<gt>
1fef88e7 84Nick Ing-Simmons E<lt>F<nik@tiuk.ti.com>E<gt>
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85
86=head1 COPYRIGHT
87
88Copyright (c) 1995 Graham Barr & Nick Ing-Simmons. All rights reserved.
89This program is free software; you can redistribute it and/or modify it
90under the same terms as Perl itself.
91
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92=cut
93
94package FindBin;
95use Carp;
96require 5.000;
97require Exporter;
7d161605 98use Cwd qw(getcwd cwd abs_path);
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99use Config;
100use File::Basename;
d250f4d1 101use File::Spec;
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102
103@EXPORT_OK = qw($Bin $Script $RealBin $RealScript $Dir $RealDir);
104%EXPORT_TAGS = (ALL => [qw($Bin $Script $RealBin $RealScript $Dir $RealDir)]);
105@ISA = qw(Exporter);
106
8fc8005d 107$VERSION = "1.49";
34da6cec 108
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109
110# needed for VMS-specific filename translation
111if( $^O eq 'VMS' ) {
112 require VMS::Filespec;
113 VMS::Filespec->import;
114}
115
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116sub cwd2 {
117 my $cwd = getcwd();
118 # getcwd might fail if it hasn't access to the current directory.
119 # try harder.
120 defined $cwd or $cwd = cwd();
121 $cwd;
122}
a73990fd 123
f5094128 124sub init
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125{
126 *Dir = \$Bin;
127 *RealDir = \$RealBin;
128
129 if($0 eq '-e' || $0 eq '-')
130 {
131 # perl invoked with -e or script is on C<STDIN>
a73990fd 132 $Script = $RealScript = $0;
34da6cec 133 $Bin = $RealBin = cwd2();
1cc0bb18 134 $Bin = VMS::Filespec::unixify($Bin) if $^O eq 'VMS';
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135 }
136 else
137 {
138 my $script = $0;
139
140 if ($^O eq 'VMS')
141 {
8fc8005d 142 ($Bin,$Script) = VMS::Filespec::rmsexpand($0) =~ /(.*[\]>\/]+)(.*)/s;
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143 # C<use disk:[dev]/lib> isn't going to work, so unixify first
144 ($Bin = VMS::Filespec::unixify($Bin)) =~ s/\/\z//;
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145 ($RealBin,$RealScript) = ($Bin,$Script);
146 }
147 else
148 {
386d1046 149 my $dosish = ($^O eq 'MSWin32' or $^O eq 'os2');
f5f423e4 150 unless(($script =~ m#/# || ($dosish && $script =~ m#\\#))
8b88ae92 151 && -f $script)
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152 {
153 my $dir;
d250f4d1 154 foreach $dir (File::Spec->path)
af08d52d 155 {
d250f4d1 156 my $scr = File::Spec->catfile($dir, $script);
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157
158 # $script can been found via PATH but perl could have
159 # been invoked as 'perl file'. Do a dumb check to see
160 # if $script is a perl program, if not then keep $script = $0
161 #
162 # well we actually only check that it is an ASCII file
163 # we know its executable so it is probably a script
164 # of some sort.
165 if(-f $scr && -r _ && ($dosish || -x _) && -s _ && -T _)
a73990fd 166 {
d250f4d1 167 $script = $scr;
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168 last;
169 }
170 }
171 }
8b88ae92 172
a73990fd 173 croak("Cannot find current script '$0'") unless(-f $script);
8b88ae92 174
7d161605 175 # Ensure $script contains the complete path in case we C<chdir>
8b88ae92 176
34da6cec 177 $script = File::Spec->catfile(cwd2(), $script)
d250f4d1 178 unless File::Spec->file_name_is_absolute($script);
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179
180 ($Script,$Bin) = fileparse($script);
181
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182 # Resolve $script if it is a link
183 while(1)
184 {
185 my $linktext = readlink($script);
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186
187 ($RealScript,$RealBin) = fileparse($script);
a73990fd 188 last unless defined $linktext;
8b88ae92 189
51a19bc0 190 $script = (File::Spec->file_name_is_absolute($linktext))
a73990fd 191 ? $linktext
d250f4d1 192 : File::Spec->catfile($RealBin, $linktext);
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193 }
194
195 # Get absolute paths to directories
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196 if ($Bin) {
197 my $BinOld = $Bin;
198 $Bin = abs_path($Bin);
199 defined $Bin or $Bin = File::Spec->canonpath($BinOld);
200 }
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201 $RealBin = abs_path($RealBin) if($RealBin);
202 }
203 }
204}
205
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206BEGIN { init }
207
208*again = \&init;
209
a73990fd 2101; # Keep require happy