in reply to Getting around Win32 limitations

What provided in this reply is garbage, but a small change should largely improve it. Use waitpid, instead of wait. If you call waitpid in this way: waitpid($child, 1), it will not blocking the main process. You just from time to time, come back and checking return code form this call, if it is -1, it means the child process died, and you get an alarm. This can be wrapped into an implementation of alarm, which is not implemented in active perl. 
my $child_pid = fork();
if ($child_pid) {
      $ret = wait($child_pid, 1);
      do {
          ... #whatever you want;
      } until ($ret == -1);
      print "got alarm\n";
} else {
   sleep($seconds);
}

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Re: Re: Getting around Win32 limitations
by pg (Canon) on Nov 10, 2002 at 06:37 UTC
    I wrapped the thing up: 
    alarm_pg.pm:
package pg_alarm;

use strict;

sub new {
    shift;
    my $seconds = shift;

    my $self = {};
    $self->{CHILD_PID} = fork();
    if ($self->{CHILD_PID} == 0) {
        sleep($seconds);
    }
    bless $self;
    return $self;
}

sub alarmed {
    my $self = shift;

    my $result = 0;
    if (defined($self->{CHILD_PID})) {
        my $ret = waitpid($self->{CHILD_PID}, 1);
        if ($ret == -1) {
            $result = 1;
        } 
    }
    return $result;
}

1;


test.pl:
use pg_alarm;
use strict;

my $a = pg_alarm->new(10);
while (!$a->alarmed()) {
    #print "haven't gotten alarm yet\n";
}
print "got alarm\n";

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