impossiblerobot has asked for the wisdom of the Perl Monks concerning the following question:

I spent some time with Super Search, looking for a way for a module to find its own location, but didn't have any luck. This is the best solution I could come up with:

MyModule.pm (self-locating module)
----------- 
package MyModule;

use strict;

my $inc_dir;

LOOP:
foreach my $inc (@INC)
{
    opendir(DIR, $inc) or next;
    while (my $module = readdir(DIR))
    {
        if ($module eq 'MyModule.pm')
        {
            $inc_dir = $inc;
            closedir(DIR);
            last LOOP;
        }
    }
    closedir(DIR);
}

print "MyModule found at: $inc_dir\n";

1;

[download]
mymodule.plx (test script)
------------ 
#!/usr/bin/perl -w

# Test MyModule.pm

use strict;

use MyModule;

print "Done.\n";

[download]
With this solution, there is a (IMHO small) chance for a race condition. Is there a better way to do this?

Impossible Robot

Replies are listed 'Best First'.
Re: Module Self-Location
by japhy (Canon) on Feb 08, 2002 at 16:28 UTC
    Embrace the %INC hash. $INC{"MyModule.pm"}

    _____________________________________________________
    Jeff[japhy]Pinyan: Perl, regex, and perl hacker.
    s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;

[reply]
      Thanks, japhy! I spent a lot of time searching all over the place because I thought I had seen an easy way to do this. But I had forgotten that %INC was setting there holding just exactly the information I was looking for. :-)

      Update: Here's my updated self-locating module: 
      package MyModule;

use strict;

my $inc_dir = $INC{'MyModule.pm'};

$inc_dir =~ s!/MyModule.pm$!!;

print "MyModule found at: $inc_dir\n";

1;

      [download]
      Update 2: After a little more searching, I finally found the original node I was looking for: Read a static file from module directory.

      Impossible Robot
[reply]
[d/l]
Re: Module Self-Location
by hakkr (Chaplain) on Feb 08, 2002 at 16:28 UTC
    The full path to a script is held in the special variable $0. Maybe there is one for a scripts modules ?
[reply]
      Well, $0 only holds a relative path. For the full path, you should use FindBin's $Bin and $Script.

      _____________________________________________________
      Jeff[japhy]Pinyan: Perl, regex, and perl hacker.
      s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;

[reply]
[reply]

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