With forks (*nix), when you have multiple processes all waiting to accept on a shared socket, when a client connects, *every* listening process receives the connect.
That would be horrible, but fortunately it's not true. If multiple processes waiting for a connection on the same socket, when client connects, *only one* listening process
accepts connection. Here's a simple example that demonstrates it:
use 5.010;
use strict;
use warnings;
use IO::Socket::INET;
my $sock = IO::Socket::INET->new(LocalPort => 7777, Listen => 10);
for (1..3) {
my $pid = fork;
unless($pid) {
my $cli = $sock->accept;
say "Process $$ accepted connection from " . $cli->peerport;
print while <$cli>;
exit 0;
}
}
Try to connect to 7777 and you will see that only one process will accept connection. Hence there's no need to have any global mutexes.
