Execute at the same time? Why do you need that?

Even if you use any feature of parallel programming, execute both at the same time can be hard to do it. If I'm not wrong, it will be impossible if you try to do it in a computer with a single processor/single thread, for example.

If you just want to make them run in parallel in the sense you want to start one and do not wait for it to finish to launch the second sub, you can use fork or threads. The best one depends on the OS you're running your program.

Check for Parallel::Fork module in CPAN. You should take a look at POE too, but the learning curve is longer then Parallel::Fork.

See threads.

Simplest solution:

use threads;
...

while(1) {
    async( \&sub1, $hash1 )->detach;
    async( \&sub2, $hash2 )->detach;
    sleep(600);
}

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Here I want to access get the values returned values from the subs, by using threads I have wrote the code as below:

use threads;
use Data::Dumper;

my $hash1;
my $hash2;

while(1) {
    async( \&sub1)->detach;
    async( \&sub2)->detach;

    print '$hash1'. Dumper($hash1) ."\n";
    print '$hash2'. Dumper($hash2) ."\n";
    print "_______________________________\n";
    sleep(10);
}

sub sub1
{
        my $now = `date "+%Y-%m-%d %H:%M:%S"`;
        chomp($now);
        $hash1->{'time'} = $now;
}


sub sub2
{
        my $now = `date "+%Y-%m-%d %H:%M:%S"`;
        chomp($now);
        $hash2->{'time'} = $now;
}

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But when I execute this program getting the values like:
$hash1$VAR1 = undef;
$hash2$VAR1 = undef;
_______________________________
Here I want to get the values of both hash in Main program;
how can I do this..
Thanks

There are several ways of achieving your goal. I cannot infer which is appropriate from your sample code.

Here are two ways:

#! perl -sw
use strict;
use threads;
use threads::shared;
use Data::Dumper;

my %hash1 :shared;
my %hash2 :shared;

while(1) {
    async( \&sub1)->detach;
    async( \&sub2)->detach;

    sleep(2);
    lock %hash1; lock %hash2;
    print '$hash1'. Dumper(\%hash1) ."\n";
    print '$hash2'. Dumper(\%hash2) ."\n";
    print "_______________________________\n";
}

sub sub1
{
        my $now = scalar localtime;
        lock %hash1;
        $hash1{'time'} = $now;
}


sub sub2
{
        my $now = scalar localtime;
        lock %hash2;
        $hash2{'time'} = $now;
}

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#! perl -sw
use strict;
use threads;
use Data::Dumper;

my %hash1;
my %hash2;

while(1) {
    my( $t1 ) = threads->create( \&sub1 );
    my( $t2 ) = threads->create( \&sub2 );

    sleep(2);
    %hash1 = $t1->join;
    %hash2 = $t2->join;
    print '$hash1'. Dumper(\%hash1) ."\n";
    print '$hash2'. Dumper(\%hash2) ."\n";
    print "_______________________________\n";
}

sub sub1
{
        my $now = scalar localtime;
        return time => $now;
}


sub sub2
{
        my $now = scalar localtime;
        return time => $now;
}
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Try them, note the differences, and ask questions.

---

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

"I'd rather go naked than blow up my ass"

MCE has been released for Perl. This is how one could do this with MCE. Not knowing what you're wanting to do in the main caller, the example has 2 callback functions.

Both workers run in parallel below. Workers never exit due to running inside a never ending loop. The do method passes data back to the main process or thread.

http://code.google.com/p/many-core-engine-perl/

https://metacpan.org/module/MCE

use MCE;

sub proc1 {
   my $hash_ref = shift;
   for (keys %{ $hash_ref }) {
      print $_, ': ', $hash_ref->{$_}, "\n";
   }
}

sub proc2 {
   my $hash_ref = shift;
   for (keys %{ $hash_ref }) {
      print $_, ': ', $hash_ref->{$_}, "\n";
   }
}

my $mce = MCE->new(
   max_workers => 2,

   user_func => sub {
      my ($self) = @_;

      while (1) {
         if ($self->wid == 1) {
            my %hash1 = ( 'key1' => 'value1' );
            $self->do('proc1', \%hash1);
         }
         else {
            my %hash2 = ( 'key2' => 'value2' );
            $self->do('proc2', \%hash2);
         }
         sleep(600);
      }
   }
);

$mce->run;

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