<?php
/**
* This class show the effect of concurrance by accessing the same file from different parallel processes.
* log.txt will be managed by default php functions
* log2.txt will be managed by CuncurrentFile.php
*
* If you run this file, you will se that log.txt have less contents.
* *
*/
error_reporting(E_ALL);
include_once ("../ConcurrentFile.php");
define("FORKS", 5); // number of parallel processes
define("SLEEP",10000); // amount of sleeping time of each process in microseconds
$pid = getmypid();
$path = __FILE__;
//--- multi-process managment
$aCliOpts = getopt('a:');
if ($aCliOpts !== false) //it's a fork
{
$parent_pid = $aCliOpts['a'];
}
else //no, create some forks
{
$parent_pid = "root";
for ($i = 0; $i < FORKS; $i++)
{
execInBackground("php \"$path\" -a $pid");
}
}
function execInBackground($cmd) {
if (substr(php_uname(), 0, 7) == "Windows"){
pclose(popen("start /b $cmd", "r"));
}
else {
exec($cmd . " > /dev/null &");
}
}
//-- end
$content = "pid: $pid <= parent_pid: $parent_pid \n ";
$content2 = file_get_contents("log.txt");
$file = new ConcurrentFile("log2.txt");
$file->writeLock();
$content2s = $file->read();
usleep(10000);
$file->write($content.$content2s)->close();
file_put_contents("log.txt",$content.$content2);
?>
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