note 62084 deleted from function.flock by danbrown
| From: | danbrown@php.net | Date: | Mon, 18 May 2009 00:39:02 +0000 |
| Subject: | note 62084 deleted from function.flock by danbrown | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-155405@lists.php.net to get a copy of this message | ||
Note Submitter: jbr at ya-right dot com
----
On Windows ISAPI testing a file or directory with flock does not return
TRUE OR FALSE, it just results in a system hang until the prior flock
called has been released. So it is sometimes better to create a fake
locking system that gives you complete control of the IO handle so you
can exist or move on if the lock is not released at a certain number
of tries or time, to get at the file!
// PHP 5 example
<?
$file = './log.txt'; // the file we are writing to
$data = "add this\r\n"; // data to add
$write_type = 'a'; // append to the file
$lock_name = './lock'; // the fake locking file name
$lock_tries = 10; // the number of times to try and open the file
// usage
if ( fake_lock ( $file, $data, $write_type, $lock_name, $lock_tries ) === true )
{
echo 'data written to file';
}
else
{
echo 'could not write data to file!';
}
function fake_lock ( $fl_file, $fl_data, $fl_write, $fl_name, $fl_try )
{
$fl_done = false;
$fl_count = 0;
$fl_key = md5 ( uniqid ( microtime () ) );
do
{
$fl_count++;
if ( ! file_exists ( $fl_name ) )
{
file_put_contents ( $fl_name, $fl_key );
$fl_test = file_get_contents ( $fl_name );
if ( $fl_test == $fl_key )
{
$fl_done = true;
}
}
if ( ! $fl_done )
{
if ( $fl_count == $fl_try )
{
return ( false );
}
else
{
usleep ( 10000 );
}
}
} while ( ! $fl_done );
$io = fopen ( $fl_file, $fl_write );
fputs ( $io, $fl_data );
fclose ( $io );
unlink ( $fl_name );
return ( true );
}
?>