http://qs1969.pair.com?node_id=144188


in reply to Re: making fork() a flag, and wait()ing properly
in thread making fork() a flag, and wait()ing properly

Nice! Your last example of:

foreach my $node ( @devices ) {
    if( $do_fork ) {
        my $pid = fork();
        if( !$pid ) {
            do_exciting_things();
            exit 0;
        }
    } else {
        do_exciting_things();
    }
}

[download]

looks very much like my most recent rewrite after starting this thread, so i am very encouraged that I am actually starting to understand what it is you dudes actually are talking about :-)

maybe though you could clear up the fog for me on this:

use POSIX;
my $do_fork = 1;
$SIG{CHLD} = sub {
    while( ( my $pid = waitpid(-1, POSIX::WNOHANG()) ) > 0 ){
        ...
    }
}

[download]

this one has me scratching my head. if you'd rather point to a perldoc reference, i'm up for that as well. it looks as though you're defining a subroutine as a hash value, but i'm not certain where/how its being called.

thanks -c

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Re: Re: Re: making fork() a flag, and wait()ing properly
by lestrrat (Deacon) on Feb 08, 2002 at 19:41 UTC

    Are you asking me about just the syntax? or about signal handling with %SIG ?

    As far as the syntax goes, my code is equivalent to something like this: 

       my $coderef = sub{ .... };
   ## now $coderef is a reference to a subroutine,
   ## which can be executed like this:
   ##
   ##    $coderef->(); # $coderef->( @args )
   ##

   $SIG{ CHLD }= $coderef;

    [download]

    So that means you can actually create an anonymous subroutine, and assign it to a scalar. Which in turn can be assigned to a hash value :)

    As for the signal handling portion, perldoc perlipc will give you more information. Not sure what is the best resource for that... ( I could try to explain, but I'm not confident that my knowledge is 100% correct )

[reply]
[d/l]

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