[Back]

MacOS X Developer Preview Release Notes Copyright © 1999-2000 by Apple Computer, Inc. All Rights Reserved.

Mac OS X Developer Preview Release Notes:
Open Transport

On Mac OS X, Open Transport notifiers, timer tasks and deferred task do not run to completion. That means that code from the main event loop or another thread may preempt code running from OT notifiers, OT timer tasks and OT deferred tasks. The solution is to always protect data by using either atomic operations or by calling OTEnterNotifier()/OTLeaveNotifier().

On Mac OS X, OT deferred tasks are not run by the Deferred Task Manager but are rather handled by the Open Transport framework itself. This ensure serialization between OT notifiers and OT deferred tasks without incurring performance overhead.

Although on Mac OS 8 and 9 you can create other kind of OT configurations, only the followings are supported by Carbon:

• "tcp", "tilisten,tcp", "udp" and "rawip" for TCP/IP endpoints;
• "dnr" for TCP/IP mapper and Internet services providers;
• "ddp" for AppleTalk endpoints;
• "nbp" for AppleTalk mapper and services providers;
• "ppp" for OT/PPP API control endpoints.

With Carbon, one cannot pass options into OT configuration strings for the same reason that OTCreateOptions() and OTCreateOptionString() are not part of the Carbon API.

When building a CFM Carbon application on Mac OS 8/9 with MPW or Code Warrior, do not link with any of the Open Transport libraries as the resulting CFM Carbon application would run on Mac OS 8 or 9 but would fail to launch on Mac OS X because there's no CFM Open Transport libraries.

Known problems

• If you call OTBind() with a qlen greater than 0 in the bind request, the endpoint can only listen for incoming connections. Subsquently, you may call OTAccept() on this endpoint but calling OTConnect() will fail with kEOPNOTSUPPErr.
• The disconnection reason returned by OTRcvDisconnect() may be in the wrong error code range.
• In some case, when several out-of-band data is sent by the peer, out-of-band data may be read as normal data.
• No events are notified on OT/PPP control endpoints.
• Opening a raw IP endpoint require superuser privileges on Mac OS X.
• Current values of association related options are not retrieved by OTListen(), OTRcvUData() and OTRcvConnect().