Re: Why does count() make copies of arrays?

On Mon, 2006-08-14 at 17:20 -0400, Robert Cummings wrote: > On Mon, 2006-08-14 at 13:16 -0400, Adam Zey wrote: > > I was writing a shell script in PHP (4.4.2) that dealt with a rather > > large array. To figure out what I needed the new memory limit to be, I > > did a memory_get_usage() at the end of my script, and came up with about > > 5.5MB. I then set the memory limit to 8MB. > > > > When I tried to run it, the script ran out of memory on the line: > > > > $numwords = count($words); > > > > However, when I switched to simply incrementing $numwords every time I > > added an element to $words, the memory limit of 8MB was fine. > > > > So my question is, if PHP does copy-on-write, why does PHP make a copy > > of an array when you use count() on it, which should NOT be modifying > > the array? > > For some reason the memory_get_usage() function wouldn't appear in my > PHP compilation even after using the --enable-memory-limit flag, and > rather than dig very deep, I whipped up the following script to test > your issue (under PHP 4.2.2): That last line should have said 4.4.2 :) Cheers, Rob. -- .------------------------------------------------------------. | InterJinn Application Framework - http://www.interjinn.com | :------------------------------------------------------------: | An application and templating framework for PHP. Boasting | | a powerful, scalable system for accessing system services | | such as forms, properties, sessions, and caches. InterJinn | | also provides an extremely flexible architecture for | | creating re-usable components quickly and easily. | `------------------------------------------------------------'