multitasking - listening to a socket while remaining interactive or doing other tasks

[John V. Pataki]

I am trying to write an perl/Tk application that will allow user interaction while at the same time monitoring a socket for other apps that want to talk to it.

I seem to be able to do either or...

 

I can write a simple server to listen to the socket as in the example below....

 

(examples from O'reilly)

-----------------------------

use Socket;
use Carp;
sub logmsg { print "@_ at ", scalar localtime, "\n" }

 

my $port = shift || 2345;
my $proto = getprotobyname('tcp');

 

socket(Server, PF_INET, SOCK_STREAM, $proto) or die "socket: $!";
setsockopt(Server, SOL_SOCKET, SO_REUSEADDR, pack("l", 1))
                                             or die "setsockopt: $!";
bind(Server, sockaddr_in($port, INADDR_ANY)) or die "bind: $!";
listen(Server,SOMAXCONN)                     or die "listen: $!";

 

logmsg "server started on port $port";
my $paddr;
$SIG{CHLD} = \&REAPER;

 

for ( ; $paddr = accept(Client,Server); close Client) {
    my($port,$iaddr) = sockaddr_in($paddr);
    my $name = gethostbyaddr($iaddr,AF_INET);
    logmsg "connection from $name [",
            inet_ntoa($iaddr), "] at port $port";
    print Client "Hello there, $name, it's now ",
                    scalar localtime, "\n";
}

-----------------------------------------

 

 

or even a simpler one like this

 

 

----------------------------------------

 

use IO::Socket;
$sock = new IO::Socket::INET (LocalHost => 'localhost',
                              LocalPort => 1200,
                              Proto     => 'tcp',
                              Listen    => 5,
                               Reuse     => 1                            
                             );
die "Socket could not be created. Reason: $!" unless $sock;
while ($new_sock = $sock->accept()) {
    while (defined ($buf = <$new_sock>)) {
       print $buf;
    }
}
close ($sock);

 

---------------------------------------------------------

 

and I have written several perk/Tk apps that do various items.

 

But once, I add the socket listening code to the perl/Tk app... I am locked.

Is there a way to have the same app listen to a socket and remain unlocked to do other tasks?

 

It seems to me it would involve somehow making the listen or accept commands operate in an eval block or something.

But I haven't gotten that to work yet.

 

Thanks for any help,

 

John