pmload - show what files a given module loads at compile time

Given an argument of a module name, show all the files that are loaded directly or indirectly when the module is used at compile-time.

    $ pmload IO::Handle
    /usr/local/devperl/lib/5.00554/Exporter.pm
    /usr/local/devperl/lib/5.00554/Carp.pm
    /usr/local/devperl/lib/5.00554/strict.pm
    /usr/local/devperl/lib/5.00554/vars.pm
    /usr/local/devperl/lib/5.00554/i686-linux/DynaLoader.pm
    /usr/local/devperl/lib/5.00554/i686-linux/IO/Handle.pm
    /usr/local/devperl/lib/5.00554/Symbol.pm
    /usr/local/devperl/lib/5.00554/i686-linux/IO/File.pm
    /usr/local/devperl/lib/5.00554/SelectSaver.pm
    /usr/local/devperl/lib/5.00554/i686-linux/Fcntl.pm
    /usr/local/devperl/lib/5.00554/AutoLoader.pm
    /usr/local/devperl/lib/5.00554/i686-linux/IO.pm
    /usr/local/devperl/lib/5.00554/i686-linux/IO/Seekable.pm

    $ cat `pmload IO::Socket` | wc -l
       4015

    $ oldperl -S pmload Tk
    /usr/lib/perl5/site_perl/Tk/Pretty.pm
    /usr/lib/perl5/Symbol.pm
    /usr/lib/perl5/site_perl/Tk/Frame.pm
    /usr/lib/perl5/site_perl/Tk/Toplevel.pm
    /usr/lib/perl5/strict.pm
    /usr/lib/perl5/Exporter.pm
    /usr/lib/perl5/vars.pm
    /usr/lib/perl5/site_perl/auto/Tk/Wm/autosplit.ix
    /usr/lib/perl5/site_perl/auto/Tk/Widget/autosplit.ix
    /usr/lib/perl5/site_perl/Tk.pm
    /usr/lib/perl5/i386-linux/5.00404/DynaLoader.pm
    /usr/lib/perl5/site_perl/auto/Tk/Frame/autosplit.ix
    /usr/lib/perl5/site_perl/auto/Tk/Toplevel/autosplit.ix
    /usr/lib/perl5/Carp.pm
    /usr/lib/perl5/site_perl/auto/Tk/autosplit.ix
    /usr/lib/perl5/site_perl/Tk/CmdLine.pm
    /usr/lib/perl5/site_perl/Tk/MainWindow.pm
    /usr/lib/perl5/site_perl/Tk/Submethods.pm
    /usr/lib/perl5/site_perl/Tk/Configure.pm
    /usr/lib/perl5/AutoLoader.pm
    /usr/lib/perl5/site_perl/Tk/Derived.pm
    /usr/lib/perl5/site_perl/Tk/Image.pm
    /usr/lib/perl5/site_perl/Tk/Wm.pm
    /usr/lib/perl5/site_perl/Tk/Widget.pm

If the programmers used a delayed CWrequire, those files won't show up. Furthermore, this doesn't show all possible files that get opened, just those that those up in CW%INC. Most systems have a way to trace system calls. You can use this to find the real answer. First, get a baseline with no modules loaded.

    $ strace perl -e 1 2>&1 | perl -nle '/^open\("(.*?)".* = [^-]/ && print $1'
    /etc/ld.so.cache
    /lib/libnsl.so.1
    /lib/libdb.so.2
    /lib/libdl.so.2
    /lib/libm.so.6
    /lib/libc.so.6
    /lib/libcrypt.so.1
    /dev/null

    $ strace perl -e 1 2>&1 | grep -c '^open.*= [^-]'
    8

Now add module loads and see what you get:

    $ strace perl -MIO::Socket -e 1 2>&1 | grep -c '^open.*= [^-]'
    24

    $ strace perl -MTk -e 1 2>&1 | grep -c '^open.*= [^-]'
    35

Devel::Loaded, plxload(1).

Copyright (c) 1999 Tom Christiansen

This is free software. You may modify it and distribute it under Perl's Artistic Licence. Modified versions must be clearly indicated.