Is there a sequence of loading extensions / modules in PHP?

We installed the PHP extension for the memcached server http://pecl.php.net/package/memcached using pecl install memcached, which ended with the instruction to add "extension = memcached.so" to php.ini, while we did, we kept getting error http://pecl.php.net/bugs/bug.php?id=17574&edit=1 .

So, we removed this line “extension = memcached.so” from php.ini and added this line to the /etc/php.d/memcached.ini file, and everything worked fine.

leaves me a question .. is there a specific sequence in which PHP loads the extension / modules, and how will the sequence matter?