Re^3: multithreading sample needed

[zentara]

in reply to Re^2: multithreading sample needed
in thread multithreading sample needed

Here is another way to slow things down for visualization. Add a delay in the thread sub.

sub thread {
   my $val = shift;

   foreach my $x (1..10) {
       print "hello $x from thread $val\n";

       my $delay = int rand 5;
       sleep $delay;
   }
}

it seems that perl's idea of multithreading is just as good as calling the avarage subroutine :/

On a single cpu machine, that is true.

In real world work, threading is more useful as a means of easily sharing variables between different code blocks running independently, using threads::shared. Otherwise, forking is usually a better parallel processing solution because of issues like memory reclamation, independence of IO, sharing objects, and a few others gotchas which threads occaisionally cause. For example, look how easy it is for the main thread and the child thread can share the array:

#!/usr/bin/perl
use warnings;
use threads;
use threads::shared;
use strict;

$|=1; #turn off buffering

my @hosts_shared : shared; #declare as shared before setting value

@hosts_shared = (1,2,3,4,5);

print "@hosts_shared\n";

my $thread = threads->new(sub {
    print "Run the thread! array should be modified\n";
    #modify shared array
    push @hosts_shared, 42;
})->detach();

sleep 1; # cheap hack to allow thread time to work

print "@hosts_shared\n";

print "Hit enter to exit\n";
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