For Ctrl^C or kill -INT, use a signal handler:
$SIG{INT} = sub { $dbh->disconnect if $dbh };
AFAIK, nothing you can do about kill -9; perhaps you oughtn't to be using -9 habitually? | [reply]
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to make sure that most signals will trigger the closing, use an END-block:
END {
$dbh->disconnect
}
in conjunction with sigtrap to trap al signals (which are trappable!):
use sigtrap qw(die normal-signals);
Paul
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Both ysth and rev_1318 make excellent points. But, be careful with SIG handlers. 'kill -9' should be an ultimately last resort if nothing else works, not just a way to kill a script. If you read the perldoc on signals and the POSIX module POD, you should get a much better idea of what (and what not) to do.
Because I have read those, and know a bit about signals, I will mention one thing further; try to avoid setting $SIG{KILL} unless you're positive you know what you're doing. If your KILL handler doesn't work properly, you may find yourself up a very smelly stream without an appropriate nautical navigation tool. ;-)
radiantmatrix
require General::Disclaimer;
s//2fde04abe76c036c9074586c1/; while(m/(.)/g){print substr(' ,JPacehklnorstu',hex($1),1)}
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On my system at least, you can't catch KILL. This code prints KILL signal caught when KILL is caught:
[gifford@gifford gifford]$ perl -e'$SIG{KILL}=sub { die "KILL signal c
+aught"; }; sleep(10)' &
[1] 4316
[gifford@gifford gifford]$ kill -9 4316
[gifford@gifford gifford]$
[1]+ Killed perl -e'$SIG{KILL}=sub { die "KILL signa
+l caught"; }; sleep(10)'
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Yes, that is how it should work. However, I have seen the occasional two-stage KILL signal, where kill -9 sends SIGKILL only truly destroys the process if the SIG is not handled by the application after few ticks.
I don't know how common that is, but it's still unwise to set $SIG{KILL} unless you know for sure it will be safe to do so.
radiantmatrix
require General::Disclaimer;
s//2fde04abe76c036c9074586c1/; while(m/(.)/g){print substr(' ,JPacehklnorstu',hex($1),1)}
| [reply] |
I'd like to add another layer of complexity. I connect to MySQL from a CGI::Application web app. CA recommends using a teardown sub to disconnect as follows:
sub teardown {
my $self = shift;
# Disconnect when we're done
$self->param('DBH')->disconnect();
} # teardown
Is this sufficient, or should I also worry about those cases where the script dies in midstream?
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