#! perl -slw
use strict;
use threads qw[ async ];

sub sub1 {
	my $no = shift;
   while(1) {
       print "in sub $no";
       select undef, undef, undef, 0.1;
   }
}

async \&sub1, 1; ## Param = '1'
sub1( 2 ); ## Param = '2'
__END__
P:\test>397011
in sub 2
in sub 1
in sub 2
in sub 1
in sub 2
in sub 1
Terminating on signal SIGINT(2)