This section provides information on the NMS TUP:
C language definitions for all information element structures, event structures, and associated constants are provided in the tupmsgs.h file.
Applications must code information elements not relevant to their application as NOT_PRESENT.
Each information element within an event contains a presence indicator to specify whether or not to include it in an outgoing event, or whether or not it was received in an incoming event.
Presence indicators are coded with the following values (definitions included in tupmsgs.h):
#define NOT_PRESENT 0 /* field not present in incoming msg
* or not to be populated in outgoing msg */
#define PRESENT 1 /* field is present in incoming msg or
* should be included in outgoing msg */