NAME

Spread - Perl extension for the Spread group communication system

SYNOPSIS

            

              
              
 use Spread;
 # Connect
 my($mbox, $private_group) = Spread::connect( {
spread_name => '4444@host.domain.com',
private_name => 'mrcool',
} );
 # If you don't give a private name, you'll get a unique name from the spread daemon.
 my($mailbox, $private_group) = Spread::connect(
   spread_name => '4444@host.domain.com',
 );
 # Join and leave groups
 my(@group_to_join) = ( 'GroupA', 'GroupB', 'GroupC' );
 my(@joined_groups) = grep( Spread::join($mbox, $_), @group_to_join );
 print "Spread::join -- $sperrno"
        unless (Spread::leave($mbox, 'GroupC'));
 # Multicast to group(s)
 Spread::multicast($mbox, AGREED_MESS, 'GroupB', 0, "Hey you!");
 Spread::multicast($mbox, SAFE_MESS, @joined_groups, 0, "Hey yall!");
 # Poll mailbox
 my($messsize) = Spread::poll($mbox);
 if(defined($messsize)) { print "Next message: $messsize bytes\n"; }
 else { print "Spread::poll $sperrno\n"; }
 # Receive messages (see spread's man pages for more description)
 my($service_type, $sender, $groups, $mess_type, $endian, $message) =
Spread::receive($mbox);
 my($service_type, $sender, $groups, $mess_type, $endian, $message) =
Spread::receive($mbox, 1.789);  # 1.789 second timeout on receive
 # Disconnect
 if(Spread::disconnect($mbox)) { print "Successful disconnect\n"; }
 else { print "Spread::disconnect -- $sperrno\n"; }
            
          

DESCRIPTION

Understanding through practice ;)

See man pages for SP_connect, SP_join, SP_multicast, SP_receive, SP_poll, SP_error, SP_leave, SP_disconnect.

$sperrno holds either the integer spread error or a descriptive string depending on the context in which $sperrno is used.

Exported constants

The predefined groups of exports in the use statements are as follows:

use Spread qw(:SP);

Exports the Spread::connect, Spread::join, Spread::multicast, Spread::receive, Spread::poll, Spread::error, Spread::leave, and Spread::disconnect as SP_connect, SP_join, SP_multicast, SP_receive, SP_poll, SP_error, SP_leave, and SP_disconnect, respectively.

use Spread qw(:ERROR);

Exports all of the error conditions. Please refer to the SP_* C man pages as the "RETURN VALUES" there have both identical spellings and meanings.

use Spread qw(:MESS);

Exports all of the message types (this is returned as service type by the Spread::receive function and is the request service type of the Spread::multicast function). The actual meaning of these orderings and assurances are not simple to explain without a basic understanding of group communication systems. For more information on this topic, please visit the Spread web site at http://www.spread.org/

All constants in alphabetical order:

            

              
              
ACCEPT_SESSION
AGREED_MESS
BUFFER_TOO_SHORT
CAUSAL_MESS
CAUSED_BY_DISCONNECT
CAUSED_BY_JOIN
CAUSED_BY_LEAVE
CAUSED_BY_NETWORK
CONNECTION_CLOSED
COULD_NOT_CONNECT
FIFO_MESS
HIGH_PRIORITY
ILLEGAL_GROUP
ILLEGAL_MESSAGE
ILLEGAL_SERVICE
ILLEGAL_SESSION
ILLEGAL_SPREAD
LOW_PRIORITY
MAX_SCATTER_ELEMENTS
MEDIUM_PRIORITY
MEMBERSHIP_MESS
REGULAR_MESS
REG_MEMB_MESS
REJECT_ILLEGAL_NAME
REJECT_MESS
REJECT_NOT_UNIQUE
REJECT_NO_NAME
REJECT_QUOTA
REJECT_VERSION
RELIABLE_MESS
SAFE_MESS
SELF_DISCARD
TRANSITION_MESS
UNRELIABLE_MESS
            
          

AUTHOR

Theo Schlossnagle <jesus@cnds.jhu.edu>

SEE ALSO

Various spread documentation at http://www.spread.org/.