perl5.10

This works as expected since Perl 5.10.1: SIGINTs are trapped. #!/usr/bin/perl use strict; use warnings; $SIG{INT} = sub { die "Caught a sigint $!" }; sleep(20); But here SIGINTs are not trapped. #!/usr/bin/perl use strict; use warnings; $SIG{INT} = sub { die "Caught a sigint $!" }; END { sleep(20); } This can be fixed by setting the handler again in the END block, like so: END { $SIG{INT} = sub { die "Caught a sigint $!" }; sleep(20); } But that won't work if you have more than one block: handlers must be set again for every block. I've tried to figure this out and I can't find an explanation

In a Perl daemon reacting to various events I'm trying to use a Null object pattern in 2 cases by creating anonymous subroutines, which should just return a value of 1 aka "true" (please scroll to the right to see the check subroutines for LOGIN and ALIVE events): package User; our %EVENTS = ( LOGIN => {handler => \&handleLogin, check => sub {1}, }, CHAT => {handler => \&handleChat, check => \&mayChat, }, JOIN => {handler => \&handleJoin, check => \&mayJoin, }, LEAVE => {handler => \&handleLeave, check => \&mayLeave, }, ALIVE => {handler => sub {}, check => sub {1}, }, BID => {handler => \

Update: Salva correctly points out that I was wrong about the introduction of the "Q" pack template. It's the ">" modifier that doesn't go back to 5.8. Perl 5.10 introduced the pack() modifier ">", which, for my use case with "Q" packs an unsigned quad (64bit) value in big endian . Now, I'm looking for an efficient equivalent for pack("Q>2", @ints) where @ints contains two 64bit unsigned ints. "Q>2" means "pack two unsigned quads in big-endian byte order". Obviously, I want this because I am (at least temporarily) tied to a pre-5.10 Perl. Update2: Actually, on further reflection, something as

Some of the new features of Perl 5.10 and 5.12, such as "say", are defined as features, that you can enable or disallow explicitly using the "feature" pragma. But other additions, like the named capture groups of regexes, are implicit. When I write Perl using a 5.10+ interpreter, but want it to also run on 5.8, can I make Perl complain about using anything that's not in 5.8? Obviously, it is good practice to test your code on all major versions you intend it to run on, but it'd still be nice to have Perl warn me automatically. When I want to ensure that a program will run under particular

Starting in Perl 5.10, it is now possible to lexically scope the context variable $_ , either explicitly as my $_; or in a given / when construct. Has anyone found good uses of the lexical $_ ? Does it make any constructs simpler / safer / faster? What about situations that it makes more complicated? Has the lexical $_ introduced any bugs into your code? (since control structures that write to $_ will use the lexical version if it is in scope, this can change the behavior of the code if it contains any subroutine calls (due to loss of dynamic scope)) In the end, I'd like to construct a list