Hi Folks, I have recently discoverred a strange behaviour of forking and shared memory under windows. Below is the code in concern:
#!C:/Perl/bin/perl -w
use strict;
use Win32::MMF::Shareable;

if( fork )
{
  my $ns = tie( my %share, 'Win32::MMF::Shareable', 'share' ) || die;
  sleep 1;
  $share{parent} = 1;
  # select undef, undef, undef, 2.0;   <----- dummy line
}
else
{
  my $ns = tie( my %share, 'Win32::MMF::Shareable', 'share' ) || die;
  $share{child} = 1;
}

[download]

When I remove the dummy line, which is commented anyway, the code crashes Perl with "Free to wrong pool <address> not <address> during global destruction" error. When I leave the dummy line, the code executes without problem, on my machine anyway.

I am out of ideas as why this is happenning. Can anyone see what might be causing this strange behaviour? I have researched on the web, and I found the following description:

usually under ithreads when the interpreter context is wrong and a memory from the wrong pool is allocated.

What does this mean? Does it have anything to do with the behavious I am getting?

Thanks for your suggestions.

Update:
I put a '!' (negation) in front of fork, and it seems not to crash any more. It seems that the parent must finish first?

if( ! fork )
{
  my $ns = tie( my %share, 'Win32::MMF::Shareable', 'share' ) || die;
  sleep 1;
  $share{parent} = 1;
}
else
{
  my $ns = tie( my %share, 'Win32::MMF::Shareable', 'share' ) || die;
  $share{child} = 1;
}

[download]

In reply to Perl forking and shared memory strangeness under Windows by Roger

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