Legacy Document

Inside Macintosh: Networking With Open Transport / Part 2 - Open Transport Reference

Chapter 22 - Endpoints Reference / Functions

Functions for Connectionless Transaction-Based Endpoints /

OTCancelUReply

Cancels a request that you have read using the OTRcvURequest function.

C INTERFACE

OSStatus OTCancelUReply(EndpointRef ref, OTSequence seq);

C++ INTERFACE

OSStatus TEndpoint::CancelUReply(OTSequence seq);

PARAMETERS

ref

The endpoint reference of the endpoint that has sent the request being canceled.

seq

A long, specifying the transaction ID of the request being cancelled. Specify the same value as that value passed in the req parameter to the OTRcvURequest function that you used to read this request.

If you specify 0 for this parameter, Open Transport cancels all outstanding incoming requests for the endpoint. If you specify an invalid sequence number, Open Transport does not do anything.

function result

If the function completes successfully, it returns the kOTNoErr result; it does not return any other kind of acknowledgment.

DISCUSSION

The OTCancelUReply function cancels the incoming request whose transaction ID is specified by the seq parameter.

When you call the OTRcvURequest function, the endpoint provider allocates memory for internal buffers and assigns a sequence value to identify this transaction. Calling the OTCancelUReply function tells the provider that you are no longer interested in the transaction and that it can free up the memory and the sequence number associated with the cancelled transaction.

It is your responsibility to deallocate memory that you have reserved for the address, options, and data buffers associated with the cancelled OTRcvURequest function.

Use the OTCancelUReply function to cancel an incoming request; use the OTCancelURequest function to cancel an outgoing request.