Sharing variables across Apache threads with threads::shared
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Hi,
I'm having trouble with the basics of sharing a variable across
multiple Apache threads using threads::shared . The only code snippet
I've been able to find on this subject is from the list archives from
last month:
http://gossamer-threads.com/lists/modperl/modperl/77651#77651
I'm stuck at a much earlier stage than that, so I'm a bit lost in the
details of that code - I think I'm working along the same sort of lines
though.
My code is as follows:
---
package MyApache::MagicNumber;
use strict;
use warnings;
use threads;
use threads::shared;
use Apache::Const -compile => qw(OK);
use Apache::RequestRec ();
use Apache::RequestIO ();
my $magic_number : shared;
sub post_config {
$magic_number = int(rand(100));
my $now = gmtime(time);
`echo "$now: MagicNumber initialised to $magic_number by PID $$" >>
/tmp/magicnumber.log`;
return Apache::OK;
}
sub handler {
my $r = shift;
$r->content_type('text/html');
if ($r->args =~ /increment/) {
$magic_number++;
my $now = gmtime(time);
`echo "$now: magic_number incremented to $magic_number by PID
$$" >> /tmp/magicnumber.log`;
}
print "<html><body><p>the magic number
is</p><h1>$magic_number</h1></body></html>";
return Apache::OK;
}
1;
---
This is set up in httpd.conf like this:
PerlModule MyApache::MagicNumber
PerlPostConfigHandler MyApache::MagicNumber::post_config
<Location /magicnumber>
SetHandler perl-script
PerlResponseHandler MyApache::MagicNumber
</Location>
Repeatedly calling http://localhost/magicnumber?increment indicates
that each thread is keeping its own copy of $magic_number - they are
all starting from the same initial value set in post_config, at least.
magicnumber.log contains the following:
Tue Feb 22 14:06:14 2005: MagicNumber initialised to 63 by PID 17452
Tue Feb 22 14:06:15 2005: MagicNumber initialised to 2 by PID 17454
Tue Feb 22 14:06:20 2005: magic_number incremented to 3 by PID 17459
Tue Feb 22 14:06:21 2005: magic_number incremented to 4 by PID 17459
Tue Feb 22 14:06:22 2005: magic_number incremented to 5 by PID 17459
Tue Feb 22 14:06:23 2005: magic_number incremented to 6 by PID 17459
Tue Feb 22 14:06:24 2005: magic_number incremented to 7 by PID 17459
Tue Feb 22 14:06:38 2005: magic_number incremented to 3 by PID 17462
Tue Feb 22 14:06:38 2005: magic_number incremented to 4 by PID 17462
Tue Feb 22 14:06:39 2005: magic_number incremented to 5 by PID 17462
Tue Feb 22 14:06:41 2005: magic_number incremented to 6 by PID 17462
Tue Feb 22 14:06:45 2005: magic_number incremented to 3 by PID 17458
Tue Feb 22 14:06:46 2005: magic_number incremented to 4 by PID 17458
Tue Feb 22 14:06:50 2005: magic_number incremented to 7 by PID 17462
I've checked that threads::shared is working correctly outside of
mod_perl (via the examples on
http://www.perl.com/pub/a/2002/06/11/threads.html ) - any suggestions
where I'm going wrong?
I'm running mod_perl 1.99_12 on Apache 2.0.47 with Perl 5.8.0.
Thanks,
- Matthew
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Sharing variables across Apache threads with threads::shared
Matthew Westcott 15:02 on 22 Feb 2005
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