Legacy Document

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

Chapter 21 - Providers Reference / Functions

Controlling a Provider's Modes of Operation

A provider's mode of operation determines whether the provider runs synchronously or asynchronously, whether the provider blocks, and whether the provider acknowledges sends.

By default, providers created synchronously operate in synchronous mode; providers created asynchronously operate in asynchronous mode. You can use the OTSetSynchronous or OTSetAsynchronous function to specify how provider functions should execute. You can find out the current setting by calling the OTIsSynchronous function. If synchronous functions are in progress on a provider, you can cancel all of them by calling the OTCancelSynchronousCalls function.

A provider's blocking status affects how it interacts with a client. In servicing a client's request, a provider might be able to deal with the request immediately, or it might have to queue the request and deal with it later. You can set a provider's blocking status by calling the OTSetBlocking or OTSetNonBlocking function. You can find out a provider's current blocking status by calling the OTIsNonBlocking function. By default, providers do not block. For more information about blocking, see the section "Setting a Provider's Blocking Status".

You can use the OTAckSends and OTDontAckSends functions to specify whether a provider acknowledges sends. This determines whether a provider copies data that you send. To determine whether a provider acknowledges sends, you call the OTIsAckingSends function. By default, providers do not acknowledge sends. Mapper and individual service providers like AppleTalk and TCP/IP ignore the setting of this attribute. However, the behavior of endpoint functions that send data is affected by the endpoint provider's acknowledgment status.