$ perl if ($^O eq 'linux') { $LINUX=1; }; use if $LINUX, 'MIDI::ALSA' => ('SND_SEQ_EVENT_PORT_UNSUBSCRIBED', 'SND_SEQ_EVENT_SYSEX'); __END__ $ perl -MMIDI::ALSA Can't locate MIDI/ALSA.pm in @INC (@INC contains: /home/aitap/perl5/lib/perl5/i486-linux-gnu-thread-multi-64int /home/aitap/perl5/lib/perl5/i486-linux-gnu-thread-multi-64int /home/aitap/perl5/lib/perl5 /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl .). BEGIN failed--compilation aborted.