I have a section of code extracted from a larger prog with this problem. Tried to pare it down as much as possible. The code is this:

!/bin/perl -w
use strict;
use Readonly;

Readonly my $DBG_ANY    => -1;
Readonly my $DBG_INFO    => 0x0004;
Readonly my $DBG_KEYS    => 0x0008;
Readonly my $DBG_RAND    => 0x0080;

my @Vals = ( $DBG_ANY, 1, 2,
#    $DBG_INFO, $DBG_KEYS, 
    );

Readonly my $_debug_ops => ($DBG_RAND | $DBG_KEYS | $DBG_INFO);

printf "debugops = 0x%04x\n",$_debug_ops;
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When I run it, I get:

Argument "=28" isn't numeric in printf at ./dbgtst line 16.
debugops = 0x0000
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If I uncomment the line with "$DBG_INFO, $DBG_KEYS", the program runs as I'd expect and gives output:
debugops = 0x008c
If I put the init of _debug_ops before the "@Vals", then I always get the error from above (i.e. - whether comment is there or not).

I have to be missing something incredibly obvious and just can't see the trees for the forest.

Can anyone see why the above is not working or is something broken in perl (seems too simple to be that).
I'm running 5.8.8 and it fails the same way on both linux and under cygwin.
A cluestick would be appreciated...:-)
TIA...
Linda