ensure-default-process-pool

Arguments: &key if-exists if-does-not-exist forget kill [make-process-pool and set-process-pool keyword arguments]

There is no default process-pool when Lisp is started. Calling this function before the first attempt to use the default process-pool will create the initial default process-pool. (Trying to use it prior to calling this function, by, say, evaluating (process-pool-run nil ...) will cause and error to be signaled.)

That process pool may itself later be deleted by user action (such as calling discard-process-pool). In any case, when this function returns there will be a default process-pool.

The default process-pool is the process-pool that is used when a process-pool operator (such as process-pool-run) is called with nil as the value of the pool argument.

If the default process-pool exists when this function is called, the behavior depends on the value of the if-exists keyword argument. The possible values are:

• :supersede: Discard the current default process-pool (with discard-process-pool) and create a new one (with make-process-pool). The forget and kill keyword argument values are passed to discard-process-pool. Keyword arguments other than forget, kill, if-exists, and if-does-not-exist are passed on to make-process-pool.
• :cerror: Signal a continuable error. Replace the current default process-pool if that continuation is chosen.
• :error: Signal an error.
• Any other value: Keep and return the current default process-pool after applying set-process-pool to it, called with any set-process-pool keyword arguments passed to ensure-default-process-pool. This is the default behavior.

If no default process-pool exists when this function is called, the behavior depends on the value of the if-does-not-exist keyword argument. The possible values are:

• :create: Create and return a new process-pool, made with make-process-pool called with any make-process-pool keyword arguments passed to ensure-default-process-pool. This is the default behavior.
• Any other value: Signal a simple error.

See Process pools in multiprocessing.htm for more information on process pools.

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This page is new in the 10.1 release.
Created 2019.8.20.