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

Chapter 22 - Endpoints Reference / Functions

Functions for Connectionless Transactionless Endpoints

You can use a connectionless transactionless endpoint to transfer data after the endpoint is bound and while it is in the T_IDLE state. Connectionless transactionless service used by protocols such as DDP, or IP is described at greater length in the section "Using Connectionless Transactionless Service". This section describes the functions used to send and receive data, OTSndUData and OTRcvUData. You use the TUnitData structure with these functions to specify the data being transferred.

Due to the nature of connectionless transactionless service, you are not notified if the data fails to reach its destination. Some endpoint implementations do not detect an error in the attempt to send a datagram until after the OTSndUData function has returned successfully. In this case, Open Transport uses the T_UDERR event to notify the client sending the data. You can receive the event either by calling the OTLook function or by including this case in your notifier function. To determine why the OTSndUData function failed, you must call the OTRcvUDErr function, which is also described in this section.

SEE ALSO

Table 4-4.