By: lbjay

lbjay — Wed, 04 Mar 2009 12:51:49 +0000

testing something...


use threads;
my $foo = 1;
my $thr = threads->create(&increment)
$thr->join();
print $foo, "n";
sub increment {
    $foo++;
    print $foo, "n";
}

By: lbjay

lbjay — Wed, 04 Mar 2009 12:45:49 +0000

I know nothing of the internals. Superficially I know perl has its own threading mechanism called "ithreads". They're like POSIX threads in a lot of ways, but the key difference is that variables aren't shared between threads unless explicitly requested. Each thread gets a copy of all the current process data.instead.

For example...

use threads;
my $foo = 1;
my $thr = threads->create(&increment)
$thr->join();
print $foo, "n";
sub increment {
$foo++;
print $foo, "n";
}

This is going to print "2" and then "1". If you're used to POSIX threads you'd think the increment() subroutine is ++-ing a $foo shared with the main scope, but it doesn't; the thread increments its own copy. If you want $foo to be shared you have to enabled shared data and also declare $foo differently...

use threads;
use threads::shared;
my $foo :shared = 1;
...

By: Jonathan Rochkind

Jonathan Rochkind — Tue, 03 Mar 2009 23:35:59 +0000

How does thread handling work in Perl? Does Perl provide any facilities for it, or are you stuck using the OS system primitives?

Comments on: Basic Block Data Decomposition in Perl

By: lbjay

By: lbjay

By: Jonathan Rochkind