use strict;
use warnings;

warn "Version $]";
warn "Prototype", prototype "CORE::sleep";



my $sleepcounter;


BEGIN {

    *CORE::GLOBAL::sleep =  sub {
        warn  "start wrapper ($_[0])";
        $sleepcounter += int $_[0];
        goto &CORE::sleep;

    };
}


warn "return: ", sleep 2.3;

warn "total sleep( $sleepcounter )";