The ToolTalk service provides two methods of addressing messages:
process-oriented messages and object-oriented messages.
Process-Oriented Messages |
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Process-oriented messages are addressed to processes. Applications
that create a process-oriented message address the message to either
a specific process or to a particular type of process. Process-oriented
messages are a good way for existing applications to begin communication
with other applications. Modifications to support process-oriented
messages are straightforward and usually take a short time to implement.
Determining Message Delivery |
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To determine which groups receive messages, you scope your
messages. Scoping limits the delivery of messages to a particular
session or file.
A session is a group of processes that have an instance of
the ToolTalk message server in common. When a process opens communication
with the ToolTalk service, a default session is located (or created
if a session does not already exist) and a process identifier (procid)
is assigned to the process. Default sessions are located either
through an environment variable (called process tree sessions) or
through the X display (called X sessions).
The concept of a session is important in the delivery of messages.
Senders can scope a message to a session and the ToolTalk service
will deliver it to all processes that have message patterns that
reference the current session. To update message patterns with the
current session identifier (sessid), applications join the session.
A container for data that is of interest to applications is
called a file in this book.
The concept of a file is important in the delivery of messages.
Senders can scope a message to a file and the ToolTalk service delivers
it to all processes that have message patterns that reference the
file without regard to the process's default session. To update
message patterns with the current file path name, applications join
the file.
You can also scope a message to a file within a session. The
ToolTalk service will deliver the message to all processes that
reference both the file and session in their message patterns.
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