Wow ++BrowserUK, this is so cool. I've never done threaded perl before and in fact had to build a threaded perl in my test environment to work with this. I think after some reflection I get how this works, but there are two things I'm not getting.

The first (and biggest) is: how is the printing working? I don't see anything to ensure that writes from two different threads don't "collide" and corrupt the output file. Is that somehow taken care of automatically?

The second (and minor) thing is how to get a limit of, say $limit concurrent threads running. Would something simple like this be appropriate? I just keep a counter of the number of active threads. I do realize I could probably do this smarter by storing the threads in a hash keyed by chromosome or something like that -- just checking if the general approach of run, check for joins, add when joining is complete -- is appropriate.

Update: the code I had before was fatally flawed in so many ways I'm embarrassed. Here's a corrected version (with the original tarnished one at the bottom)

my @waiting = @chromosomes;
my %threads;
my $max_threads = 10;

while ( scalar(@waiting) || scalar( keys(%threads) ) ) {

        if ( scalar( keys(%threads) ) < $max_threads ) {
                my $chr = pop(@waiting);
                $threads{$chr} = threads->new(\&threading_function, $c
+hr);
                }

        else {

                foreach my $chr ( keys(%threads) ) {

                        if ( $threads{$chr}->is_joinable() ) {
                                $threads{$chr}->join();
                                delete $threads{$chr};
                                }

                        }

                }

        }

[download]



my $limit = 10;
my $processes = 0;
my $processed = scalar(@chromosomes);
my @threads;

while ($processed) {

    if ( scalar(@threads) < $limit ) {
        push @threads, threads->new( \&thread, $_ );
        ++$processes;
        }
    else {

        foreach my $thread (@threads) {

            if ( $thread->is_joinable() ) {
                $thread->join();
                --$processes;
                }

            }
        }
    }

[download]

Many thanks again -- you've opened up my eyes/mind to threaded programming!

In reply to Re^2: Forking Multiple Regex's on a Single String (use threads) by bernanke01
in thread Forking Multiple Regex's on a Single String by bernanke01

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