An application can connect to the log stream in different ways.
Some of these are:
- One connection per address space: Once a
program has connected to a log stream, any task running in the same
address space shares the connect status and can use the same stream
token to issue other system logger services. Any task in the address
space can disconnect the entire address space from the log stream
by issuing the IXGCONN REQUEST=DISCONNECT service.
- One connection per program: One or more
tasks in a single address space can issue IXGCONN REQUEST=CONNECT
individually to connect to the same log stream and receive separate
stream tokens. Each program must disconnect from the log stream individually.
- Multiple systems connecting to a log stream:
Multiple address spaces on one or more MVS™ systems
can connect to a single coupling facility log stream, but each one must issue
IXGCONN individually to connect and then disconnect from the log stream.
Each one receives a unique stream token; address spaces cannot share
a stream token.
When an application issues IXGCONN to connect to a coupling facility log stream,
the system logger address space connects to the coupling facility list structure
for the log stream.
Each task that issues IXGCONN REQUEST=CONNECT to connect to a log
stream must later issue IXGCONN REQUEST=DISCONNECT to disconnect from
the log stream. When a task disconnects from the log stream, the stream
token that identified the connection is invalidated. Any requests
that use the stream token after the disconnect will be rejected.
If a task that issued the IXGCONN REQUEST=CONNECT request ends
before issuing a disconnect request, system logger will automatically
disconnect the task from the log stream. This means that the unique
log stream connection identifier, or the STREAMTOKEN, will no longer
be valid. The application will receive an “expired logstream token”
error response if it then uses this same STREAMTOKEN after the task
has been disconnected on subsequent logger service requests.