Joining Multiple Sessions

When you join multiple sessions, you will automatically get responses to requests and point-to-point messages but you will not get notices unless you explicitly join the new session. The following code sample shows how to join the multiple sessions.

tt_default_session_set(new_session_identifier);
tt_open();
tt_session_join(new_session);

In order to effectively use multiple sessions, you must store the session ids of the sessions in which you are interested in order to pass these identifiers to tt_default_session_set prior to opening a new session with tt_open; that is, you need to place the values (which ttsession stores in the environment variable _SUN_TT_SESSION) in a file on the system so that other ToolTalk clients can access the value of a session id contained in that file and use it to open the non-default session. For example, you can store the session ids in a "well-known" file and then send a file-scoped message (indicating this file) to all clients which have registered an appropriate pattern. The client will then know to open the scoped-to file, read one or more session ids from it, and use these session ids (with tt_open) to open a non-default session. An alternative method is advertising the session ids by means of, for example, a name service or a third-party database.

Note - How ttsession session ids are stored and passed to interested clients is beyond the scope of the ToolTalk protocol and must be determined based on the architecture of the system.

Joining Files of Interest

When you join a file, the ToolTalk service automatically adds the name of the file to your file-scoped message patterns. For example, if you have declared a process type or registered a message pattern that specifies TT_FILE or TT_FILE_IN_SESSION, use the tt_file_join function() to join files of interested. Table 9-3 lists the ToolTalk functions you use to express your interest in specific files.

Table 9-3 ToolTalk Functions for Joining Files of Interest

When you no longer want to receive messages that reference the file, use the tt_file_quit() function to remove the file name from your file-scoped message patterns.