extra code in pp_concat, Take 2
[p5sagit/p5-mst-13.2.git] / lib / FindBin.pm
CommitLineData
a73990fd 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 "$FindBin::Bin/../lib";
a73990fd 15
8b88ae92 16 or
a73990fd 17
18 use FindBin qw($Bin);
d7791a84 19 use lib "$Bin/../lib";
a73990fd 20
21=head1 DESCRIPTION
22
23Locates the full path to the script bin directory to allow the use
24of paths relative to the bin directory.
25
26This allows a user to setup a directory tree for some software with
1fef88e7 27directories E<lt>rootE<gt>/bin and E<lt>rootE<gt>/lib and then the above example will allow
a73990fd 28the use of modules in the lib directory without knowing where the software
29tree is installed.
30
84dc3c4d 31If perl is invoked using the B<-e> option or the perl script is read from
a73990fd 32C<STDIN> then FindBin sets both C<$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
11cd4567 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
11cd4567 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
f5094128 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:
11cd4567 58
59 delete $INC{'FindBin.pm'};
60 require FindBin;
61
a73990fd 62=head1 KNOWN BUGS
63
11cd4567 64If perl is invoked as
a73990fd 65
66 perl filename
67
68and I<filename> does not have executable rights and a program called I<filename>
84dc3c4d 69exists in the users C<$ENV{PATH}> which satisfies both B<-x> and B<-T> then FindBin
a73990fd 70assumes that it was invoked via the C<$ENV{PATH}>.
71
72Workaround is to invoke perl as
73
74 perl ./filename
75
76=head1 AUTHORS
77
d250f4d1 78FindBin is supported as part of the core perl distribution. Please send bug
79reports to E<lt>F<perlbug@perl.org>E<gt> using the perlbug program included with perl.
80
81Graham Barr E<lt>F<gbarr@pobox.com>E<gt>
1fef88e7 82Nick Ing-Simmons E<lt>F<nik@tiuk.ti.com>E<gt>
a73990fd 83
84=head1 COPYRIGHT
85
86Copyright (c) 1995 Graham Barr & Nick Ing-Simmons. All rights reserved.
87This program is free software; you can redistribute it and/or modify it
88under the same terms as Perl itself.
89
a73990fd 90=cut
91
92package FindBin;
93use Carp;
94require 5.000;
95require Exporter;
8b88ae92 96use Cwd qw(getcwd abs_path);
97use Config;
98use File::Basename;
d250f4d1 99use File::Spec;
a73990fd 100
101@EXPORT_OK = qw($Bin $Script $RealBin $RealScript $Dir $RealDir);
102%EXPORT_TAGS = (ALL => [qw($Bin $Script $RealBin $RealScript $Dir $RealDir)]);
103@ISA = qw(Exporter);
104
f5094128 105$VERSION = "1.44";
a73990fd 106
f5094128 107sub init
a73990fd 108{
109 *Dir = \$Bin;
110 *RealDir = \$RealBin;
111
112 if($0 eq '-e' || $0 eq '-')
113 {
114 # perl invoked with -e or script is on C<STDIN>
115
116 $Script = $RealScript = $0;
117 $Bin = $RealBin = getcwd();
118 }
119 else
120 {
121 my $script = $0;
122
123 if ($^O eq 'VMS')
124 {
4f44ac69 125 ($Bin,$Script) = VMS::Filespec::rmsexpand($0) =~ /(.*\])(.*)/s;
a73990fd 126 ($RealBin,$RealScript) = ($Bin,$Script);
127 }
128 else
129 {
386d1046 130 my $dosish = ($^O eq 'MSWin32' or $^O eq 'os2');
f5f423e4 131 unless(($script =~ m#/# || ($dosish && $script =~ m#\\#))
8b88ae92 132 && -f $script)
a73990fd 133 {
134 my $dir;
d250f4d1 135 foreach $dir (File::Spec->path)
a73990fd 136 {
d250f4d1 137 my $scr = File::Spec->catfile($dir, $script);
f5f423e4 138 if(-r $scr && (!$dosish || -x _))
a73990fd 139 {
d250f4d1 140 $script = $scr;
8b88ae92 141
142 if (-f $0)
a73990fd 143 {
144 # $script has been found via PATH but perl could have
145 # been invoked as 'perl file'. Do a dumb check to see
146 # if $script is a perl program, if not then $script = $0
147 #
148 # well we actually only check that it is an ASCII file
149 # we know its executable so it is probably a script
150 # of some sort.
8b88ae92 151
a73990fd 152 $script = $0 unless(-T $script);
153 }
154 last;
155 }
156 }
157 }
8b88ae92 158
a73990fd 159 croak("Cannot find current script '$0'") unless(-f $script);
8b88ae92 160
a73990fd 161 # Ensure $script contains the complete path incase we C<chdir>
8b88ae92 162
d250f4d1 163 $script = File::Spec->catfile(getcwd(), $script)
164 unless File::Spec->file_name_is_absolute($script);
8b88ae92 165
166 ($Script,$Bin) = fileparse($script);
167
a73990fd 168 # Resolve $script if it is a link
169 while(1)
170 {
171 my $linktext = readlink($script);
8b88ae92 172
173 ($RealScript,$RealBin) = fileparse($script);
a73990fd 174 last unless defined $linktext;
8b88ae92 175
51a19bc0 176 $script = (File::Spec->file_name_is_absolute($linktext))
a73990fd 177 ? $linktext
d250f4d1 178 : File::Spec->catfile($RealBin, $linktext);
a73990fd 179 }
180
181 # Get absolute paths to directories
182 $Bin = abs_path($Bin) if($Bin);
183 $RealBin = abs_path($RealBin) if($RealBin);
184 }
185 }
186}
187
f5094128 188BEGIN { init }
189
190*again = \&init;
191
a73990fd 1921; # Keep require happy
193