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File: passing_vars.php

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  Classes of Luca Mariano  >  Thread  >  passing_vars.php  >  Download  
File: passing_vars.php
Role: Example script
Content type: text/plain
Description: shows variable exchange between the parent process and started pseudo-threads.
Class: Thread
A class to implement multi-threaded applications
Author: By
Last change: updated to 1.1
Date: 15 years ago
Size: 3,995 bytes
 

Contents

Class file image Download
<?php
/**
 * PHP_Fork class usage examples
 * ==================================================================================
 * NOTE: In real world you surely want to keep each class into
 * a separate file, then include() it into your application.
 * For this examples is more useful to keep all_code_into_one_file,
 * so that each example shows a unique feature of the PHP_Fork framework.
 * ==================================================================================
 * passing_vars.php
 *
 * This example shows variable exchange between the parent process
 * and started pseudo-threads. This was not possible in previous releases because
 * parent and child processes lives into different memory spaces,
 * they are separate processes with their own PID and not separate instances living
 * into the same JVM; this is just forking, not real threading...
 * This framework offers a workaround based Shared Memory usage.
 *
 * ==================================================================================
 *
 * Copyright (c) 2003-2002 by Luca Mariano (luca.mariano@email.it)
 * http://www.lucamariano.it
 *
 * This program is free software. You can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License.
 */
// Import of base class
require_once ("../Fork.php");
// number of executeThreads we want
define ("NUM_THREAD", 2);
// Class definition; as into previos example (basic.php), this class simply
// increment a counter each second; instead of printing the value to stdout,
// we'll store it into an accessible location for latter use.
class executeThread extends PHP_Fork {
    var
$counter;

    function
executeThread($name)
    {
       
$this->PHP_Fork($name);
       
$this->counter = 0;
    }

    function
run()
    {
        while (
true) {
           
// setVariable is a method inherited from PHP_Fork super class
            // it sets a variable that can be accessed thru its name
            // by parent process (calling the getVariable() method)
           
$this->setVariable('counter', $this->counter++);
           
sleep(1);
        }
    }

    function
getCounter()
    {
       
// parent process can call this facility method
        // in order to get back the actual value of the counter
       
return $this->getVariable('counter');
    }
}
// Main program. Bring up NUM_THREAD instances of the executeThread class that
// runs concurrently. It's a multi-thread app with a few lines of code!!!
// Into this example we have a console to control thread behaviour and test
// their counter value.
for ($i = 0;$i < NUM_THREAD;$i++) {
   
$executeThread[$i] = new executeThread ("executeThread-" . $i);
   
$executeThread[$i]->start();
    echo
"Started " . $executeThread[$i]->getName() . " with PID " . $executeThread[$i]->getPid() . "...\n";
}

echo
"This is the main process.\nPress [X] to terminate, [G] to read pseudo-thread's counter.\n";
// Console simple listener
while (true) {
    echo
">";

   
$opt = _getInputCLI();
    echo
"\n";
    switch (
$opt) {
        case
"X":
           
// stops all threads
           
for ($i = 0;$i < NUM_THREAD;$i++) {
               
$executeThread[$i]->stop();
                echo
"Stopped " . $executeThread[$i]->getName() . "\n";
            }
            exit;
            break;
        case
"G":
            for (
$i = 0;$i < NUM_THREAD;$i++) {
                echo
$executeThread[$i]->getName() . " returns " . $executeThread[$i]->getCounter() . "\n";
            }
            break;
    }
}
// Functions used by the console
function _getInputCLI()
{
   
$opt = _read();
   
$opt = strtoupper (trim($opt));
    return
$opt;
}

function
_read()
{
   
$fp = fopen("php://stdin", "r");
   
$input = fgets($fp, 255);
   
fclose($fp);

    return
$input;
}

?>