NAME

       TakTuk - Perl module that provides an interface to "taktuk(1)" 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 $TakTuk::error to the numeric
       code of the error that occured. A textual description of the error is provided by the
       function TakTuk::error_msg($) 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.