http://www.perlmonks.org?node_id=929096


in reply to interprocess communication

I think that you're seeing a warning, not an error. Try it without the warnings pragma. 
#!/usr/bin/perl -l

use strict;
use IPC::SysV qw(ftok IPC_CREAT S_IRWXU);

my $key = ftok("/tmp/sometest.pl", 'A');
print my $id = msgget($key, IPC_CREAT | S_IRWXU );

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