Re^2: Signals in Strawberry Perl: Name or number?

kill ALRM, $$ doesn't make sense to me!

It means "send an ALRM signal to the process with PID $$ (which mean the current process). While it may not make much sense in production code, it's certainly useful for testing.

You may want to reread the docs for kill; unlike the shell version, the perl version requires you to have the signal as first parameter, followed by the PIDs you want to send the signal to.

Comment on Re^2: Signals in Strawberry Perl: Name or number?

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Re^3: Signals in Strawberry Perl: Name or number? by Marshall (Canon) on Sep 13, 2009 at 04:33 UTC
When I test code with ALRM signal, I fiddle with the alarm($num) parameter and often use sleep() to cause the alarm to "trigger" during testing. There are problems with signal handling...in general, there is no way to "safely" continue executing a process after an ALRM signal because many OS functions are not re-entrant or even re-startable by any means. Update: I strike this last sentence because it upset some folks. No offense was intended. ~~I have no interest in obfuscated, obscure code although I do see that some folks have fun with this as an "art form".~~ The original question was, why doesn't this code work? `sub verse4 { my $boy; $SIG{ALRM} = sub { say "slip n slide" }; ride( $boy ), kill (ALRM, $$) for (1 .. 3); sleep 1; map { $_++ } ($ice_cream, $cake); } sub ride { say "Whee!" };` [download]	[reply] [d/l]
Re^4: Signals in Strawberry Perl: Name or number? by ikegami (Patriarch) on Sep 13, 2009 at 05:25 UTC
There's no difference between receiving an alarm that was sent via `alarm` or via `kill`. What makes you think that the latter can trigger signals when the former can't? What's obfuscated about sending a signal with `kill`, whose very purpose is to send signals?	[reply] [d/l] [select]
Re^5: Signals in Strawberry Perl: Name or number? by Marshall (Canon) on Sep 13, 2009 at 06:34 UTC
There's no difference between receiving an alarm that was sent via alarm or via kill. What makes you think that the latter can trigger signals when the former can't? I didn't say that there was a difference. I explained very clearly how to use the alarm signal in a normal application. A signal is a "message" from the OS. What's obfuscated about sending a signal with kill, whose very purpose is to send signals? What is obfuscated is this "poetry" idea and using language constructs in "unnatural ways". I have no problem with strange code as an art form.	[reply]
Re^6: Signals in Strawberry Perl: Name or number? by ikegami (Patriarch) on Sep 13, 2009 at 07:46 UTC


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