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Inside Macintosh: Networking /

Chapter 6 - AppleTalk Transaction Protocol (ATP) / ATP Reference

Routines / Canceling Pending ATP Functions

PRelRspCB

The PRelRspCB function cancels a PSendResponse function that is an exactly-once transaction.

FUNCTION PRelRspCB (thePBPtr: ATPPBPtr; async: Boolean): OSErr;

thePBPtr

A pointer to an ATP parameter block.

async

A Boolean that indicates whether the function should be executed asynchronously or synchronously. Specify TRUE for asynchronous execution.

-->	ioCompletion	ProcPtr	A pointer to the completion routine.
<--	ioResult	OSErr	The function result.
-->	csCode	Integer	Always relRspCB for this function.
-->	atpSocket	Byte	The number of the socket on which the request was received.
-->	addrBlock	AddrBlock	The internet socket address of the source of the request.
-->	transID	Byte	The transaction ID of the request with which the PSendResponse function to be canceled is associated.

Field Description

atpSocket

The number of the socket on which the request was received and from which the PSendResponse function that is to be canceled was sent.

addrBlock

The internet socket address of the application that issued
the request.

transID

The transaction ID of the PSendResponse call to be canceled.
You can get the transaction ID from the reqTID field of the PSendResponse parameter block queue entry.

DESCRIPTION

The PRelRspCB function releases the queued parameter block for the exactly-once transaction PSendResponse function without waiting for the release timer to expire
or for a TRel packet to be received; PRelRspCB returns a function result of noErr
for the canceled PSendResponse call.

If you call PRelRspCB to cancel a transaction that is not an exactly-once service, RelRspCB returns a function result of cbNotFound for the PSendResponse call.

ASSEMBLY-LANGUAGE INFORMATION

To execute the PRelRspCB function from assembly language, call the _Control trap macro with a value of relRspCB in the csCode field of the parameter block. To
execute this function from assembly language, you must also specify the .ATP driver reference number.

RESULT CODES

noErr	0	No error
cbNotFound	-1102	Control block not found; no pending asynchronous calls