What's the difference between sending -release or -drain to an Autorelease Pool?

Question

In many Books and on many Sites I see -drain. Well, for an Autorelease Pool that sounds cool. But does it do anything other than an release? I would guess -drain just makes

Answer 1

Oxigen is right, see the documentation for method drain of NSAutoreleasePool:

In a reference-counted environment, releases and pops the receiver; in a garbage-collected environment, triggers garbage collection if the memory allocated since the last collection is greater than the current threshold.