creation-process

Arguments: basic-pane

The default methods for this generic function return the Lisp process that called make-window to create the argument basic-pane (which is typically a window).

This function may be useful for managing windows in multiple processes, due to certain considerations that are good to keep in mind when multiple processes create windows. For example:

• Killing a process (such as by calling process-kill) will always close all of the windows that were created by that process.
• User keyboard and mouse events that occur on a window (and other messages that are programmatically sent to the window) will run code in the process that created the window.
• Creating a single window hierarchy that contains windows created in multiple processes is likely to lead to messaging timeouts or hangs when a window in one process sends a message to a window in another. (One reason is that the operating system combines the message queues of the multiple processes in this case.) This arrangement should be avoided when feasible.
• To have two sets of windows that are doing separate things simultaneously and independently, the two sets should be in separate window hierarchies and should be created by two different processes to ensure that the multiprocessing between them is responsive.

While an application could maintain its own record of which process created each window, calling creation-process may be more convenient. See About using multiple windowing threads in a Common Graphics application in cgide.htm.

Copyright (c) 1998-2002, Franz Inc. Oakland, CA., USA. All rights reserved.
Documentation for Allegro CL version 6.2. This page is new in the 6.2 release.
Created 2002.2.26.