SREQ
ATPParamBlock union
#include <AppleTalk.h>
typedef union ATPParamBlock { Size Description
ATPParms ATP; 44 General ATP parms
SendReqParms SREQ ; 52 sendrequest parms
ATPmisc1 OTH1; 46 and a few others
ATPmisc2 OTH2; 46 and a few others
Killparms KILL ; 48 and a few others
typedef ATPParamBlock *ATPPBPtr;

Notes: The .ATP Driver maintains a timer, called the release timer, for each
call to the ATPSndRsp function that is part of an exactly-once (XO)
transaction. If the timer expires before the transaction is complete (that
is, before the socket receives the transaction release packet), the driver
completes the ATPSndRsp function. Before AppleTalk Phase 2, the release
timer was always set to 30 seconds. To set the other connection end's
release timer to another value, set bit 2 of the atpFlags field in the
parameter block for the ATPSndRequest or the PNSendRequest function
and add a new byte field to the parameter block at offset 50-the TRelTime
field. (The ATPSndRequest and PNSendRequest functions use the
SendRequestParm variant of the ATP parameter block.)
The lower three bits of the TRelTime field indicate the time to which the
release timer is to be set, as follows:
TRelTime Setting of
field release timer
000 30 seconds
001 1 minute
010 2 minutes
011 4 minutes
100 8 minutes
The nodes at both ends of the ATP connection must be running AppleTalk
Phase 2 drivers for this feature to work.