PHP多连接套接字（广播问题）

Question

What I'm trying to achieve is a socket server that broadcasts some data to all connected peers. This is code of server loop:

while(TRUE) {
    $read = array();

    $read[] = $socket;

    for($i = 0; $i < $max_clients; $i++) {
        if($client_sockets[$i] != NULL) {
            $read[$i+1] = $client_sockets[$i];
        }
    }

    #This is broadcasting loop
    foreach($client_sockets as $send_sock)
    {
        socket_write($send_sock, "broadcasting".PHP_EOL);
    }

    if( socket_select($read, $write, $except, NULL) === FALSE ) {
        $errorcode = socket_last_error();
        $errormsg = socket_strerror($errorcode);
        die("Could not listen on socket : [$errorcode] $errormsg 
");
    }

    if( in_array($socket, $read) ) {
        for($i = 0; $i < $max_clients; $i++) {
            if($client_sockets[$i] == NULL) {
                $client_sockets[$i] = socket_accept($socket);

                if( socket_getpeername($client_sockets[$i], $client_address, $client_port) ) {
                    echo "Client $client_address : $client_port is now connected to us. 
";
                }

                $message = "Connected to php socket server".PHP_EOL;
                socket_write($client_sockets[$i], $message);
                break;
            }
        }
    }
}

This code works fine, accepts multiple connections and broadcasts data, except for one moment: loop starts only after I type any input from any connected client via telnet. I know this is because socket_select waits for this input, but I don't know how to start broadcasting right after client is connected.

Appreciate any help on this, because I've got feeling that I'm terribly wrong somewhere.

Answer 1

Selfown answer

Problem indeed was in socket_select($read, $write, $except, NULL); and not actually a problem. Last NULL parameter starts endless block, awaiting for client response; to make script work properly, I've changed this timeout, so it looks looks this: socket_select($read, $write, $except, 0, 500000). On the client side, however, parameter should be set to NULL(NOT 0!), so script remains idle while waiting for server broadcasting message.

I've also discovered that such blocking behavior is similar to to socket_read() and socket_write() functions, which endless by default; to change it, use socket_set_option:

socket_set_option($master_socket, SOL_SOCKET, SO_RCVTIMEO, array("sec" => 0, "usec" => 1000));
socket_set_option($master_socket, SOL_SOCKET, SO_SNDTIMEO, array("sec" => 0, "usec" => 1000));

And 1000 microseconds is as low as I could get.

Actually, I've updated answer for somebody who voted up; but I hope that solution will be useful anyway.