Re: How to set value in NSArray

[Richard Frith-Macdonald]

On 13 Jul 2004, at 19:49, James McLoughlin wrote:

> Hi
>
> A quick (naive) question on your destructor...
>
> > @implementation MyClass
> > - (void) dealloc
> > {
> >   DESTROY(monthlyRain);
> >   [super dealloc];
> > }
>
> Why is the DESTROY function used as opposed to

It's a macro ... and I just used it from habit

> [monthlyRain dealloc];

Using DESTROY is equivalent to sending a -release message and then
setting the variable to be nil.  It is *not* equivalent to -dealloc

While dealloc would be fine in this simple example, it would generally
be a bad idea in cases where the class might contain an accessor
method which could have given some other code access to monthlyRain,
so the other code might have retained it.

> ?
>
> Is this specific to gnustep, or is it also a convention in openStep / 
> Cocoa?

The DESTROY() macro is GNUstep specific, though GNUstep provides a 
header file
which can be used to make some convenience macros available in Cocoa.