Why zone is always nil while implementing NSCopying?

Question

It may be simple question, but why implementing NSCopying protocol in my class, I get zone == nil

- (id)copyWithZone:(NSZone *)zone
{
    if (zo         


        

Answer 1

Zone is a legacy from the old days when computers had 8 megs or less of RAM.

Check this out (3.1.2 Memory Allocation and Zones):

http://www.gnustep.org/resources/documentation/Developer/Base/ProgrammingManual/manual_3.html

There is also a good discussion of this over on cocoa builder (well it was on the cocoa dev mailing list) from about 10 years ago. This is exactly what @bbum was saying.

http://www.cocoabuilder.com/archive/cocoa/65056-what-an-nszone.html

Apparently this used to be documented in the Apple docs, but it was changed at some point since 2007-06-06.

http://www.cocoadev.com/index.pl?NSZone