Re^4: Win32 - Memory can not be "read"

[HuckinFappy]

Wow...it's amazing what we learn on Perlmonks! :)

Thanks, I took your advice, and did some digging. Will you be too surprised to learn I found a for() loop on line 32 of a module?

It's not our module though...it's Exception::Class. Here's the beginning of the code in that module (ending at the for() statement on line 32):

package Exception::Class;

use 5.005;

use strict;
use vars qw($VERSION $BASE_EXC_CLASS %CLASSES);

BEGIN { $BASE_EXC_CLASS ||= 'Exception::Class::Base'; }

$VERSION = '1.19';

sub import
{
    my $class = shift;

    local $Exception::Class::Caller = caller();

    my %c;

    my %needs_parent;
    while (my $subclass = shift)
    {
   my $def = ref $_[0] ? shift : {};
   $def->{isa} = $def->{isa} ? ( ref $def->{isa} ? $def->{isa} : [$def
+->{isa}] ) : [];

        $c{$subclass} = $def;
    }

    # We need to sort by length because if we check for keys in the
    # Foo::Bar:: stash, this creates a "Bar::" key in the Foo:: stash!
 MAKE_CLASSES:
    foreach my $subclass ( sort { length $a <=> length $b } keys %c )
    {

The only place we do a 'use Exception::Class', it is accompanied by a long list of our own classes of Exception we define.

again, I'm not sure what this means, but it feels like a red herring, since this code works 99.99% of the time and is exercised tens of thousands of times per day.

I see op.c got a mountain of work between 5.8.5 and 5.8.8, so now I'm hoping to get approval for testring 5.8.8 to see if the issue clears up. It's still odd that this suddenly became an issue, but perhaps some change in Windows (security patch?) aggravated a known issue in op.c?

Thanks again!

[BrowserUk]

I'd stick a trace statement (probably to a separate file), either side of that for loop.

MAKE_CLASSES:
printf $temporaryLog "%s : Enter loop %d keys ...", scalar localtime()
+, scalar keys %c;
    foreach my $subclass ( sort { length $a <=> length $b } keys %c )
    {
     ...
    }
printf $temporaryLog "exited\n";

And run that on whichever machine is giving the greatest frequency of failures. At worst, it will allow you to eliminate a red-herring. At best, it just might show you something that will take you a step closer.

In a similar vein, if you have a test machine that is demonstrating the failure regularly, or a production machine that you can sign off on having run really slowly for a while, then get Devel::Trace and use it to see where the failure is occuring.

perl -d:Trace yourscript.pl 2>yourlog

The problem with that is the logfile will be overwritten by subsequent successful runs, If you use 2>>log you might fill your disc, and you'd have a mountain of log to search through.

So, add a couple of lines to the script:

BEGIN{ close STDERR; open STDERR, '>', "$$.log" }
END{ close STDERR; unlink "$$.log"; }

That will direct the trace output to a separate file for each run and, if the program completes successfully, delete that file and prevent your disk from filling up. Any runs which terminate abnormally should leave their log files behind which should give you a pretty clear picture of where the script is terminating.

Good luck!