#! perl -slw
use strict;
use threads;

my $kid = threads->new( sub{ system 'notepad.exe', 'd:\test.txt'; } );

print 'Parent detaching';
print $kid->detach;
print 'Parent waiting';
<>;
print 'Parent finishing...';
__END__
D:\Perl\test>test
Parent detaching
Parent waiting
^Z
Parent finishing...