---
name: "TakTuk"
section: "3pm"
platform: "linux"
package: "libtaktuk-perl"
version: "3.7.7-3.1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/TakTuk"
---

# TakTuk(3pm)

Perl module that provides an interface to "taktuk(1)" communication facilities

## NAME

TakTuk - Perl module that provides an interface to "[taktuk(1)](/taktuk/1.md)" communication facilities

## SYNOPSIS

```
  use TakTuk;

  my $rank = TakTuk::get('rank');
  my $count = TakTuk::get('count');

  print "I'm process $rank among $count\n";

  if ($rank > 1) {
      my ($from, $message) = TakTuk::recv();
      if (not defined($message)) {
          print "Trying to recv: ",
                TakTuk::error_msg($TakTuk::error), "\n";
      } else {
          print "$rank received $message from $from\n";
      }
  }

  sleep 1;
  my $next = $rank+1;
  $next = 1 if ($next > $count);
  if (not TakTuk::send(to=>$next, body=>"[Salut numero $rank]")) {
      print "Trying to send to $next: ",
            TakTuk::error_msg($TakTuk::error), "\n";
  }

  if ($rank == 1) {
      my ($from, $message) = TakTuk::recv(timeout=>5);
      if (not defined($message)) {
          print "Trying to recv :",
                TakTuk::error_msg($TakTuk::error), "\n";
      } else {
          print "$rank received $message from $from\n";
      }
  }
```

## DESCRIPTION

The **TakTuk** communication layer Perl interface provides a way for programs executed using the `taktuk(1)` command to exchange data. It is based on a simple send/receive model using multicast-like sends and optionally timeouted receives.  This is only designed to be a control facility, in particular this is not a high performance communication library.

The Perl communication interface for **TakTuk** is made of functions that can be called by scripts executed using the `"taktuk_perl"` command of the **TakTuk** engine (preferred way, less installation requirements on remote machines) or using the **TakTuk** Perl module provided with the **TakTuk** distribution. These functions are:

- **TakTuk::get($)**

  gets some information from **TakTuk**. Currently available information includes 'target', 'rank', 'count', 'father', 'child\_min' and 'child\_max'. This is a better way to get this information than environment variables as its takes into account renumbering that might occur after process spawn.

- **TakTuk::send(%)**

  sends a scalar to a single peer or a set specification (see `taktuk(1)` for information about set specifications).  The two mandatory fields in the arguments are `"to"` (with a set specification) and `"body"`. Optionally, a field `"target"` might be given. Returns an undefined value upon error.

- **TakTuk::recv(%)**

  blocks until the reception of a message. Returns a list of two elements: the logical number of the source of the message and the message itself. Accepts an optional `"timeout"` argument with a numeric value. Returns an empty list upon error.

When an error occur, all these functions set the variable `$TakTuk::error` to the numeric code of the error that occurred. A textual description of the error is provided by the function `TakTuk::error_msg($)` that takes the error code as an argument.

Error codes are the following :

- TakTuk::ESWRIT

  a call to `"TakTuk::syswrite"` failed. This is due to a `"syswrite"` error different than `"EAGAIN"`. The code should be accessible using `$!`.

- TakTuk::EFCLSD

  the communication channel to the **TakTuk** engine has been closed. This typically occur when shutting down the logical network (using Ctrl-C on root node for instance).

- TakTuk::ESREAD ("TakTuk::recv" only)

  a call to `"sysread"` failed (the code should be accessible using `$!`).

- TakTuk::EARGTO ("TakTuk::send" only)

  `"to"` field missing in the arguments.

- TakTuk::EARGBD ("TakTuk::send" only)

  `"body"` field missing in the arguments.

- TakTuk::ETMOUT ("TakTuk::recv" only)

  The call to `"TakTuk::recv"` timeouted. This only occur when giving a `"timeout"` field as `"TakTuk::recv"` argument.

Finally, the **TakTuk** Perl module defines some constants which value match the different states reported by the stream `"state"` (see `taktuk(1)` for details about this stream). These constant are the following:

```
  TakTuk::TAKTUK_READY
  TakTuk::TAKTUK_NUMBERED
  TakTuk::TAKTUK_TERMINATED
  TakTuk::CONNECTION_FAILED
  TakTuk::CONNECTION_INITIALIZED
  TakTuk::CONNECTION_LOST
  TakTuk::COMMAND_STARTED
  TakTuk::COMMAND_FAILED
  TakTuk::COMMAND_TERMINATED
  TakTuk::UPDATE_FAILED
  TakTuk::PIPE_STARTED
  TakTuk::PIPE_FAILED
  TakTuk::PIPE_TERMINATED
  TakTuk::FILE_RECEPTION_STARTED
  TakTuk::FILE_RECEPTION_FAILED
  TakTuk::FILE_RECEPTION_TERMINATED
  TakTuk::FILE_SEND_FAILED
  TakTuk::INVALID_TARGET
  TakTuk::NO_TARGET
  TakTuk::MESSAGE_DELIVERED
  TakTuk::INVALID_DESTINATION
  TakTuk::UNAVAILABLE_DESTINATION
```

## SEE ALSO

`tatkuk(1)`, `taktukcomm(3)`, `TakTuk::Pilot(3)`

## AUTHOR

The original concept of **TakTuk** has been proposed by Cyrille Martin in his PhD thesis. People involved in this work include Jacques Briat, Olivier Richard, Thierry Gautier and Guillaume Huard.

The author of the version 3 (perl version) and current maintainer of the package is Guillaume Huard.

## COPYRIGHT

The `"TakTuk"` communication interface library is provided under the terms of the GNU General Public License version 2 or later.