Jeff Pang wrote:
> On 10/23/07, monk <[EMAIL PROTECTED]> wrote:
>
>> I'm having problems accessing a variable outside its subroutine.
>> I've tried several combinations too long to write here. Maybe I just
>> can't see the forest for the trees. But I'm lost. I need your
>> wisdom.
>>
>> I'd like my program below to change $status to zero to exit the loop.
>>
>> meaning...$> perl test.pl --start
>> it prints out indefinitely "hello world"
>>
>> But if $> perl test.pl --stop
>> it gets out of the loop exiting the program.
>>
>>
>>
And if you want to keep the notation similar to that above you'd need
the second instance of the script (with the --stop), to send the signal
to the process of the first instance (generally by storing the pid in a
file and then sending the signal as below if the pid is still running).
>
> Hi,
>
> When script is running,how can you re-run it with another argument to
> make it stop?
> The general way to let a running program stop is to send a signal.
> Let me modify your code to,
>
> use strict;
> use warnings;
>
> our $status = 1;
> $SIG{TERM} = $SIG{INT} = sub {$status = 0};
>
> start();
>
> sub start {
> while ($status){
> print "hello world!\n";
> sleep 1;
> }
>
> print "out of loop. Will exit now\n";
> exit 0;
> }
>
> __END__
>
>
> When you run it,you can send SIGINT or SIGTERM to let it exit gracefully.
> Given the process id is 1234,under unix you can say,
>
> $ kill -s 2 1234
>
> The script would print "out of loop. Will exit now" and exit.
> (-s 2 means sending SIGINT,see `man 7 signal` for details).
>
> The most important change for the code above is that we re-defined
> singal handlers:
> $SIG{TERM} = $SIG{INT} = sub {$status = 0};
>
> When the script receive SIGTERM or SIGINT,it set the global $status to
> 0,so the loop condition become false,the program exit.
>
>
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