zentara, thanks for yet another great worker thread example. ++. I'm pretty sure you know the techniques I use below. I hope that my alternate, goto-less approach is useful to someone.

It's possible to get rid of the gotos. I don't know that it improves readability/maintainability. I like the way that the gotos work to jump out of the loop in the original.

On with the code. Removing the first goto: 


PROCESS_DATA:
while(1){

    if( scalar @ready > 0 ){

         if( my $data = shift @to_be_processed ){
            my $t = shift(@ready);
            $shash{$t}{'data'} = $data;
            $shash{$t}{'go'} = 1; 
            print "thread $t restarting\n";
          }else{ print "out of input\n"; last PROCESS_DATA;  }
     }
} # end PROCESS_DATA

[download]

I used last to break out of the loop. I added a label to retain the readability of the goto version. It's functionally equivalent to the goto version.

Now the second and third goto: 

sub worker{
    my $thr_num = shift;
    print "$thr_num started\n"; 
    my $count;


    while(1) {

        WORKER_LOOP:
        while(1){

            if( $shash{$thr_num}{'die'} ){
            print "thread $thr_num finishing\n"; 
            return} 
            #wait for $go_control  
            if($shash{$thr_num}{'go'}){      

            if($shash{$thr_num}{'die'}){
            print "thread finishing\n"; 
            return} 

            $count++;            
            my $str = '    'x$thr_num; #printout spacer
            print $str.$thr_num.'->'.$count.$shash{$thr_num}{'data'},"
+\n";

            if ($count > 10){ last WORKER_LOOP; }

            #select(undef,undef,undef,.25);
            sleep rand 5

            }else{ 
                $count = 0;
                select(undef,undef,undef,.25); 
            }# sleep until awakened 

        } #end WORKER_LOOP


        # Recycle Thread
        $shash{$thr_num}{'go'} = 0;
        print "$thr_num done....going back to sleep\n";
        $shash{$thr_num}{'data'} = '';
        $count = 0;
        push @ready, $thr_num;
        print "pushing $thr_num\n";
    }

    return;
}

[download]

I wrapped the section bracketed by the START label and goto START with a loop. I didn't label the loop, because we never break it. It may make sense to apply a label here in some instances.

I added a label to the pre-existing loop (now an inner loop), and use last to break out of it as needed. Once again, to improve readability, I used a label where it isn't necessary.

Whether these changes are worth making, I can't say for sure. I tend to prefer the inner/outer loop arrangement I show above to zentara's loop implemented as a goto, simply because I can bounce between the enclosing brackets with my % key. I like the other gotos, and feel that they do help readability. YMMV.


TGI says moo

In reply to Re: Reusable threads demo by TGI
in thread Reusable threads demo by zentara

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