ZMQPoll::poll

(PECL zmq >= 0.5.0)

ZMQPoll::poll — Poll the items

说明

public int ZMQPoll::poll ( array &$readable , array &$writable [, int $timeout = -1 ] )

Polls the items in the current poll set. The readable and writable items are returned in the readable and writable parameters. ZMQPoll::getLastErrors() can be used to check if there were errors.

参数

readable: Array where readable ZMQSockets/PHP streams are returned. The array will be cleared at the beginning of the operation.
writable: Array where writable ZMQSockets/PHP streams are returned. The array will be cleared at the beginning of the operation.
timeout: Timeout for the operation. -1 means that poll waits until at least one item has activity. Please note that starting from version 1.0.0 the poll timeout is defined in milliseconds, rather than microseconds.

范例

Example #1 A ZMQPoll() example

Create a simple poll server


<?php

/* Create socket, request-reply pattern (reply socket) */
$context = new ZMQContext();
$server  = $context->getSocket(ZMQ::SOCKET_REP);

/* Bind to port 5555 on 127.0.0.1 */
$server->bind("tcp://127.0.0.1:5555");

/* Create new pollset for incoming/outgoing message */
$poll = new ZMQPoll();

/* Add the object and listen for poll in/out */
$id = $poll->add($server, ZMQ::POLL_IN | ZMQ::POLL_OUT);
echo "Added object with id " . $id . "\n";

/* Initialise readable and writable arrays */
$readable = array();
$writable = array();

while (true) {
   /* Amount of events retrieved */
   $events = 0;

   try {
       /* Poll until there is something to do */
       $events = $poll->poll($readable, $writable, -1);
       $errors = $poll->getLastErrors();

       if (count($errors) > 0) {
           foreach ($errors as $error) {
               echo "Error polling object " . $error . "\n";
           }
       }
   } catch (ZMQPollException $e) {
       echo "poll failed: " . $e->getMessage() . "\n";
   }

   if ($events > 0) {
       /* Loop through readable objects and recv messages */
       foreach ($readable as $r) {
           try {
               echo "Received message: " . $r->recv() . "\n";
           } catch (ZMQException $e) {
               echo "recv failed: " . $e->getMessage() . "\n";
           }
       }

       /* Loop through writable and send back messages */
       foreach ($writable as $w) {
           try {
               $w->send("Got it!");
           } catch (ZMQException $e) {
               echo "send failed: " . $e->getMessage() . "\n";
           }
       }
   }
}
?>

返回值

Returns an integer representing amount of items with activity. Throws ZMQPollException on error.