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Allegro CL version 8.2
Unrevised from 8.1 to 8.2.
8.1 version

set-signal-handler

Arguments: number function

function is made the signal handler for signal number. It replaces the previous handler for the signal instead of pushing a new handler on *signals*.

The handling of operating system dependent signals generated during program execution is not part of Common Lisp. A signal is a small integer. The list of valid signals is given in a system dependent file, usually on UNIX something like /usr/include/signals.h. Signals are either synchronous or asynchronous, but there is no distinction made in this interface--the handling of both types of signals is the same. A handler for a signal is a function of two arguments, signal number and t. If there is no handler for a particular signal, then some default action is invoked, which is usually to signal an error. Signals handlers should return a true value if they handle the signal, so that other, nested handlers are not invoked to handle the signal. A signal that is posted during a gc is processed immediately after the gc finishes.

See add-signal-handler (which has an example), remove-signal-handler, *signals*, and with-signal-handler.


Copyright (c) 1998-2016, Franz Inc. Oakland, CA., USA. All rights reserved.
This page was not revised from the 8.1 page.
Created 2010.1.21.

ToCDocOverviewCGDocRelNotesFAQIndexPermutedIndex
Allegro CL version 8.2
Unrevised from 8.1 to 8.2.
8.1 version