WebMutex Class: 'support/web_mutex.php'

The WebMutex class offers a cross-platform, named mutex solution for very old versions of PHP. Using the PECL sync extension instead is a better option since WebMutex can frequently result in a broken lock file if the application exits prematurely while a lock is held.

Example usage:

<?php
	require_once "support/web_mutex.php";

	$mutex = new WebMutex(__FILE__);
	if (!$mutex->Lock())
	{
		echo "Unable to obtain mutex.\n";

		exit();
	}

	// Do work here.

	$mutex->Unlock();
?>

WebMutex::__construct($name)

Access: public

Parameters:

• $name - A string containing a full path and filename to a web-writable location on the web server.

Returns: Nothing.

This function initializes the class.

WebMutex::Lock($block = true,$maxlock = false)

Access: public

Parameters:

• $block - A boolean the determines whether or not to wait for a lock to be acquired (Default is true).
• $maxlock - A boolean of false or an integer indicating how long a lock should exist (Default is false).

Returns: A boolean of true if the lock was successfully obtained, false otherwise.

This function attempts to obtain a lock on the mutex. The lock file is $name . ".lock".

WebMutex::Unlock()

Access: public

Parameters: None.

Returns: A boolean of true if the unlock was successful, false otherwise.

This function unlocks the mutex.

WebMutex::microtime_float()

Access: private

Parameters: None.

Returns: The result of microtime() as a float.

This is a very old function from long before microtime() had a second parameter to get a float value as a response.