My reproduction code:

<?

ini_set('display_errors',TRUE);
ini_set('memory_limit','2M');
error_reporting(E_ALL);

for ($i=0;$i<30000;$i++) {
	$func=create_function('$m','return($m);');
	unset($func);
	echo '. ';
}

echo '<h1>OK</h1>';

?>

It breaks with "Fatal error: Allowed memory size of 2097152 bytes 
exhausted..." error. Is there any way, to solve this problem?

You could write it like this:
isset($fn)?$fn:$fn=create_function('$v', 'echo $v;');

I've been waiting for a feature like this for a while and I hope it gets added.  It doesn't look very vital from the first example where its generating the same function over and over in a loop.  You could pull it out the loop and save a lot of memory.

But the real reason you need this feature is when the body of code you're creating is dynamic.  I have a library which generates code based on lots of user input and then this code is applied to large data sets.  I've been avoiding create_function because of the "leak" (I do use it in a couple less called spots).  And eval is too slow to run on each row of the data set so I'm forced to generate even more code which includes the looping and everything else and do one very large eval.  I'd rather create a function that is run on every row.  And when the processing is done, I could free that function or I could keep a cache for exact user input matches, but even that would be a limited size and would still need to free old functions.

Yes, create_function is not always needed especially with the new closures.  But it's still the best way to generate dynamic functions and it would be even better if these functions were automatically freed when there are no more references or if there was a function to manually free them.

Please try using this snapshot:

  http://snaps.php.net/php5.2-latest.tar.gz
 
For Windows:

  http://windows.php.net/snapshots/

Just built the snapshot on my Fedora 11 machine.  No change.

No feedback was provided for this bug for over a week, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".