Application Messaging

The ToolTalk Messaging Service is the application messaging mechanism for the Common Desktop Environment. Application messaging addresses inter-application control and cooperation for applications working on behalf of a single user. The ToolTalk session daemon is a local message-routing process whose control scope typically corresponds to that of the X server. This means that clients within a session issue requests, the ToolTalk session manager finds or starts some client within a session that is able to handle the request, and the ToolTalk session daemon tracks the request until completion.

The desktop provides two standard ToolTalk protocols known as messages sets. A message set contains a number of messages that can be exchanged between a sender and a handler process. These messages are grouped together because they describe related requests and notices. The sender and recipient may be within the same process or on different hosts. Message sets have associated utility functions that allow you to concentrate on the semantics of the protocol without getting involved in the low-level messaging details. Some of the message set functions enable you to defer to default behavior with almost no work on your part.

Desktop Message Set

The Desktop Message Set encompasses three areas. The first is windowing behavior. The second involves file access and short term file life cycle control. The third is specific to applications that have extension languages and is not generic enough to warrant library support.

Media Message Set

The Media Message Set allows an application to be a container for arbitrary media, or to be a media player/editor that can be driven from such a container. The Media message interface allows a container application (such as Mailer or File Manager) to compose, display, edit, or print a file or buffer of an arbitrary media type, without understanding anything about the format of that media type. ToolTalk routes a container's requests to the user's preferred tool for the given media type and operation. This includes routing the request to an already-running instance of the tool if that instance can best handle the request.