(PHP 5, PHP 7)
stream_socket_sendto — Sends a message to a socket, whether it is connected or not
$socket
   , string $data
   [, int $flags = 0
   [, string $address
  ]] ) : int
   Sends the specified data through the
   socket.  
  
socket
       The socket to send data to.
      
dataThe data to be sent.
flags
       The value of flags can be any combination
       of the following:
       
| STREAM_OOB | Process OOB (out-of-band) data. | 
address
       The address specified when the socket stream was created will be used
       unless an alternate address is specified in address.
      
If specified, it must be in dotted quad (or [ipv6]) format.
Returns a result code, as an integer.
Example #1 stream_socket_sendto() Example
<?php
/* Open a socket to port 1234 on localhost */
$socket = stream_socket_client('tcp://127.0.0.1:1234');
/* Send ordinary data via ordinary channels. */
fwrite($socket, "Normal data transmit.");
/* Send more data out of band. */
stream_socket_sendto($socket, "Out of Band data.", STREAM_OOB);
/* Close it up */
fclose($socket);
?>