Re: Timing out backquoted executions

You want an alarm, however with backticks this does leave the process hanging and there's no easy way to get its pid, but it is your child so you can do things to your process group to take it down, perhaps an END that sigkills the process group?

eval {
    local $SIG{ALRM} = sub { die "Alarma" };

    alarm 10;
    `perl -e 'while(1) {};'`;
    alarm 0;
};

if ($@ eq 'Alarma') {
    warn "alarm'd";
} elsif ($@) {
    die $@;
}
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Comment on Re: Timing out backquoted executions Download Code

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Re^2: Timing out backquoted executions by Anonymous Monk on Aug 02, 2007 at 20:10 UTC
Thanks guys. Now I'm noticing though that when I do this, the process continues running. How can I be sure to terminate this process? > cat perl.pl #!/usr/bin/perl eval { $SIG{ALRM} = sub { die "Timed out\n"; }; alarm(5); `perl -e 'while(1){sleep 1;}'`; alarm(0); }; print "Died with: $@\n"; > ./perl.pl Died with: Timed out > ps PID TTY TIME CMD 11551 pts/0 00:00:00 bash 11648 pts/0 00:00:00 perl 11651 pts/0 00:00:00 ps [download]	[reply] [d/l]
Re^3: Timing out backquoted executions by Joost (Canon) on Aug 02, 2007 at 20:19 UTC
You're probably better off using piped open (see perlopentut) in this case, since that will give you the process id of the spawned process: `# set up alarm... my $pid; $SIG{ALRM} = sub { kill $pid; die "Timed out" }; alarm(5); $pid = open PROG,"/some program\|" or die "Can't fork: $!"; my $input = join('',<PROG>); alarm(0); close PROG;` [download] Note; code is untested. update: added alarm() calls. "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply] [d/l]