Description
bool 
msg_send ( resource queue, int msgtype, mixed message [, bool serialize [, bool blocking [, int &errorcode]]] )
     msg_send() sends a message of type
     msgtype (which MUST be greater than 0) to
     the message queue specified by queue.
    
     If the message is too large to fit in the queue, your script will wait
     until another process reads messages from the queue and frees enough
     space for your message to be sent.
     This is called blocking; you can prevent blocking by setting the
     optional blocking parameter to FALSE, in which
     case msg_send() will immediately return FALSE if the
     message is too big for the queue, and set the optional
     errorcode to EAGAIN, indicating that you should
     try to send your message again a little later on.
    
     The optional serialize controls how the
     message is sent.  serialize
     defaults to TRUE which means that the message is
     serialized using the same mechanism as the session module before being
     sent to the queue.  This allows complex arrays and objects to be sent to
     other PHP scripts, or if you are using the WDDX serializer, to any WDDX
     compatible client.
    
     Upon successful completion the message queue data structure is updated as
     follows: msg_lspid is set to the process-ID of the
     calling process, msg_qnum is incremented by 1 and
     msg_stime is set to the current time.
    
     See also msg_remove_queue(),
     msg_receive(),
     msg_stat_queue() and
     msg_set_queue().