Re: how to kill background process when script exit?

can anyone tell me why this works:


#!/usr/bin/perl

my $pid = open(my $fh, "java -classpath /Users/allasso/AWS/utility/too
+ls_additional/SC_add/java TextEntry |")
    or die "Couldn't launch: $! / $?";
    
print "pid: $pid\n\ndoing stuff...\n\npress return to exit script...\n
+\n";

<STDIN>;

if ($pid) {
    kill 9 => $pid; # bang
};
[download]

and this doesn't (hangs - can't exit script until java app is closed):


#!/usr/bin/perl

my $pid = open(my $fh, "java -classpath /Users/allasso/AWS/utility/too
+ls_additional/SC_add/java TextEntry |")
    or die "Couldn't launch: $! / $?";
    
END {
    if ($pid) {
        kill 9 => $pid; # bang
    };
};

print "pid: $pid\n\ndoing stuff...\n\npress return to exit script...\n
+\n";

<STDIN>;
[download]

Comment on Re: how to kill background process when script exit? Select or Download Code

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Re^2: how to kill background process when script exit? by Corion (Patriarch) on Feb 21, 2011 at 15:24 UTC
Most likely because the second snippet does an implicit `close $fh;` [download] after the end of your program code and just before it starts to run the END block.	[reply] [d/l]
Re^3: how to kill background process when script exit? by Allasso (Monk) on Feb 21, 2011 at 15:47 UTC
I just observed that if I use `FH` instead of `my $fh` as the first arg to open(), it works	[reply] [d/l] [select]
Re^4: how to kill background process when script exit? by Corion (Patriarch) on Feb 21, 2011 at 15:56 UTC
This likely is because the globals are only cleaned up on global destruction, that is, they live until after the last END block has run. As you kill the child before that, this allows things to work as expected.	[reply]