Sequence Number


Type:	Four-byte integer of C type T_INT4
Default Value:	`0`
Valid Values:	Any integer 0 or greater

The sequence number property uniquely identifies the message for guaranteed message delivery so that duplicate messages can be detected by the receiver(s). When a message with a delivery mode of T_IPC_DELIVERY_SOME or T_IPC_DELIVERY_ALL is sent through a connection, the message sequence number is set to a unique incremented number. The receiving process(es) also records the highest sequence number it has processed. If the message is later resent because of a GMD failure, the receiver can detect the duplicated message by its reused sequence number. A sequence number of zero indicates that a message has not been sent with GMD. For a detailed discussion of GMD, see Chapter 4, Guaranteed Message Delivery.

Function to set value:

This property is set automatically and cannot be set manually.

Function to get value:

TipcMsgGetSeqNum. For example:

if (!TipcMsgGetSeqNum(msg, &seq_num)) { 
  /* error */ 
} 
TutOut("msg had reply to %s\n", reply_to_dest ? reply_to_dest : 
       "<NULL>");