14.2.7 Example

The following example allows two (or more) multiplication tables to be printed out simultaneously.

First, the function to print out a multiplication table.

(in-package "USER")

(defun print-table (number total stream)

(do ((i 1 (+ i 1)))

((> i total))

 (format stream "~S X ~S = ~S~%" number i (* i number))

 (mp:process-allow-scheduling)))

Note the use of mp:process-allow-scheduling to allow the process to be interrupted once during each iteration of the do loop.

Now we define the function that calls print-table within multiprocessing:

(defun process-print-table (name number total)

  (mp:process-run-function name nil

    #'print-table number total *standard-output*))

The nil argument is used because no keywords are specified.

process-print-table can now be called from two separate Listener windows to print out different multiplication tables simultaneously, for example:

in one Listener and:

in another Listener.