ZMQPoll::poll

Poll the items

Description

public integer ZMQPoll::poll ( array &$readable , array &$writable [, integer $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.

Parameters

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.

Examples

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 $poll->add($serverZMQ::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";
           }
       }
   }
}
?>

Return Values

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