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.IX Title "Parallel::Pipes 3pm"
.TH Parallel::Pipes 3pm 2026-06-18 "perl v5.42.2" "User Contributed Perl Documentation"
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.SH NAME
Parallel::Pipes \- parallel processing using pipe(2) for communication and synchronization
.SH SYNOPSIS
.IX Header "SYNOPSIS"
.Vb 1
\&  use Parallel::Pipes;
\&
\&  my $pipes = Parallel::Pipes\->new(5, sub ($task) {
\&    # this is a worker code
\&    my $result = do_work($task);
\&    return $result;
\&  });
\&
\&  my $queue = Your::TaskQueue\->new;
\&  # wrap Your::TaskQueue\->get
\&  my $get; $get = sub ($queue) {
\&    if (my @task = $queue\->get) {
\&      return @task;
\&    }
\&    if (my @written = $pipes\->is_written) {
\&      my @ready = $pipes\->is_ready(@written);
\&      $queue\->register($_\->read) for @ready;
\&      return $queue\->$get;
\&    } else {
\&      return;
\&    }
\&  };
\&
\&  while (my @task = $queue\->$get) {
\&    my @ready = $pipes\->is_ready;
\&    $queue\->register($_\->read) for grep $_\->is_written, @ready;
\&    my $min = List::Util::min($#task, $#ready);
\&    for my $i (0..$min) {
\&      # write tasks to pipes which are ready
\&      $ready[$i]\->write($task[$i]);
\&    }
\&  }
\&
\&  $pipes\->close;
.Ve
.SH DESCRIPTION
.IX Header "DESCRIPTION"
\&\fBNOTE\fR: Parallel::Pipes provides low\-level interfaces.
If you are interested in using Parallel::Pipes,
you may want to look at Parallel::Pipes::App instead,
which provides more friendly interfaces.
.PP
Parallel processing is essential, but it is also difficult:
.IP "How can we synchronize our workers?" 4
.IX Item "How can we synchronize our workers?"
More precisely, how to detect our workers are ready or finished.
.IP "How can we communicate with our workers?" 4
.IX Item "How can we communicate with our workers?"
More precisely, how to collect results of tasks.
.PP
Parallel::Pipes tries to solve these problems with \f(CWpipe(2)\fR and \f(CWselect(2)\fR.
.PP
App::cpm, a fast CPAN module installer, uses Parallel::Pipes.
Please look at App::cpm <https://github.com/skaji/cpm/blob/master/lib/App/cpm/CLI.pm>
or eg directory <https://github.com/skaji/Parallel-Pipes/tree/main/eg> for real world usages.
.SH "ARTIFACT ATTESTATIONS"
.IX Header "ARTIFACT ATTESTATIONS"
GitHub Artifact Attestations are generated for release tarballs uploaded to
CPAN. If you care about provenance for the uploaded tarballs, see:
.PP
<https://github.com/skaji/Parallel\-Pipes/attestations>
.SH "COPYRIGHT AND LICENSE"
.IX Header "COPYRIGHT AND LICENSE"
Copyright 2016 Shoichi Kaji <skaji@cpan.org>
.PP
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.