Fatal Error Handling

Hi, I have a set of functions which are potentially dangerous in terms of memory hogging, and need to protect from memory overflow - this is I want to detect when the memory overflow occurs. The manual says that eval() will return false on a fatal error, so I thought I could do something like the following, where it would produce a "O" for each itteration, and when it failed (memory overflow) it would continue and echo the last line. What I get however is this attached to the end. Any advice would be gratefully recieved (and perhaps, the documentation on eval updating if it can not catch all fatal errors) #! /usr/bin/php <?php $y = 0; $str = ""; $code = '$str .= $str . "."; return true;'; $x = TRUE; while($x != FALSE){ $x = eval($code); echo "O"; $y ++; } echo "\n $y it's \n\n ". $str; ?> run: $ ./intellirun2.php OOOOOOOOOOOOOOOOOOOOOO Fatal error: Allowed memory size of 8388608 bytes exhausted (tried to allocate 4194305 bytes) in /home/jt/work2/sms/web/stats/intellirun2.php(8) : eval()'d code on line 1