Sebastian Weber wrote:
> The following code sets up a UNIX domain socket server
>
<http://www.experts-exchange.com/Programming/Programming_Languages/Perl/Q_22001649.html#>
>
> and connects to that server in a different thread. I found the
> following
> code using threads to block forever - ist blocks exactly at the
> connect
> / accept calls:
>
> #!/usr/bin/perl
> use threads;
> use Socket;
>
> unlink ("/tmp/mysock");
> $t=threads->create("con_thread");
>
> socket (SOCK1,PF_UNIX,SOCK_STREAM,0) or die "socket(): $!";
> bind (SOCK1, sockaddr_un("/tmp/mysock")) or die "bind(): $!";
> listen(SOCK1,SOMAXCONN) or die "listen(): $!";
> accept (CLIENT,SOCK1);
> $t->join();
>
> sub con_thread {
> sleep(2);
> socket(SOCK2, PF_UNIX, SOCK_STREAM, 0) or die "socket(): $!";
> connect(SOCK2, sockaddr_un("/tmp/mysock")) or die "connect():
> $!";
> }
>
> Whereas the same code will not block using fork():
>
> #!/usr/bin/perl
> use threads;
> use Socket;
>
> unlink ("/tmp/mysock");
> if (fork) {con_thread();exit;}
>
> socket (SOCK1,PF_UNIX,SOCK_STREAM,0) or die "socket(): $!";
> bind (SOCK1, sockaddr_un("/tmp/mysock")) or die "bind(): $!";
> listen(SOCK1,SOMAXCONN) or die "listen(): $!";
> accept (CLIENT,SOCK1);
>
> sub con_thread {
> sleep(2);
> socket(SOCK2, PF_UNIX, SOCK_STREAM, 0) or die "socket(): $!";
> connect(SOCK2, sockaddr_un("/tmp/mysock")) or die "connect():
> $!";
> }
>
> Does anybody have any idea why?? Is there a workaround?
> BTW: Im using Perl v5.8.7 built for cygwin-thread-multi-64int
The problem is that Socket is not thread-safe. You can work around
this by loading Socket into the main thread after creating the child
thread, and loading it separately in the child thread:
#!/usr/bin/perl
use threads;
unlink ("/tmp/mysock");
my $t=threads->create("con_thread");
require Socket;
import Socket ':all';
socket (SOCK1,PF_UNIX,SOCK_STREAM,0) or die "socket(): $!";
bind (SOCK1, sockaddr_un("/tmp/mysock")) or die "bind(): $!";
listen(SOCK1,SOMAXCONN) or die "listen(): $!";
accept (CLIENT,SOCK1);
$t->join();
sub con_thread {
require Socket;
import Socket ':all';
sleep(2);
socket(SOCK2, PF_UNIX, SOCK_STREAM, 0) or die "socket(): $!";
connect(SOCK2, sockaddr_un("/tmp/mysock")) or die "connect(): $!";
}
____________________________________________________________________________________
Do you Yahoo!?
Everyone is raving about the all-new Yahoo! Mail beta.
http://new.mail.yahoo.com
