use warnings;
use strict;

BEGIN{ 
    open OLDERR, '>&', \*STDERR 
        or die "Couldn't save STDERR\n$!";
    close STDERR;
}
INIT{
    open STDERR, '>&', \*OLDERR 
        or die "Couldn't retrieve STDERR\n$!";
}

use constant PI => 3.14;
use constant PI => 1000;
print PI, "\n";