*EINTR = \4;

##</code><code>##

package ConstantVars;
use strict;
use warnings;

sub import {
    my $package = shift;
    die "Odd number of arguments to ConstantVars" if ! @_ % 2;
    my %constants = @_;
    my $caller = caller;
    while (my ($key,$value) = each %constants) {
        eval qq( *${caller}::${key} = \\"${value}" );
    }
}

1;

##</code><code>##

use strict;
use warnings;

use ConstantVars (
    PI => 3.14159,
    VERSION => 1.01,
);

print "PI is $PI in version $VERSION\n";

##</code><code>##

PI is 3.14159 in version 1.01