in reply to Signals in Strawberry Perl: Name or number?
A "signal" is a way for your program to process "asynchronous" events. Meaning
that you register a subroutine to be called when that event occurs. When you do
this, you don't have to explictly keep checking that a particular event
occured, the OS
will call the sub when that event occurs.
kill ALRM, $$ doesn't make sense to me!
The below code shows a simple example of a handler for SIGALRM.
Kill $some_number makes no sense if $some_number is not a PID. kill ALRM doesn't have a PID. ALRM on my system is "numeric 14", but that is just shorthand for what the string ALRM means.#!/usr/bin/perl -w use strict; #$|=1; #see note below... $SIG{'ALRM'} = 'timeout'; alarm(1); while (1){sleep(1);} sub timeout { print "stdout: Alarming!\n"; print STDERR "stderr: Alarming!\n"; exit(0); }; __END__ prints: Note: stderr msg comes first because "autoflush" for stdout wasn't turned on (stdout normally doesn't get "flushed" until program end). $|=1; turns autoflush on. stderr: Alarming! stdout: Alarming!
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Re^2: Signals in Strawberry Perl: Name or number?
by Crackers2 (Parson) on Sep 13, 2009 at 02:06 UTC | |
by Marshall (Canon) on Sep 13, 2009 at 04:33 UTC | |
by ikegami (Patriarch) on Sep 13, 2009 at 05:25 UTC | |
by Marshall (Canon) on Sep 13, 2009 at 06:34 UTC | |
by ikegami (Patriarch) on Sep 13, 2009 at 07:46 UTC |
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