Re: Possible MacOS X compier problem

[Bill Northcott]

David Ayers <d.ayers@inode.at> wrote on 24/07/2003 06:11:34 PM:
> Maybe you could post the full implmenetation of the setQuotedObject:
> method and it's declaration in the coresponding header file.  I'm
> starting to believe that you're a victim of a change in convention from
> the pre OpenStep days.  Back in the early days, methods were supposed to
> always return self, unless they had other meaningful values to return.
> Therefor an unspecified signature in the header:
> -setSomeValue:value;
> impliied
> - (id)setSomeValue:(id)value;

This definitely seems to be the issue.  A quick search and replace added 
the explicit type specifier (id) to some 2700 method declarations and 
implementations in 431 files.  This appears to have no effect on the 
libraries built with the FSF compiler, but fixes the nesting issue when 
built with the Apple compiler.

> I really doubt this is a compiler error.  Maybe Apple tweaked thier
> compiler to somehow support the legacy interpretation, and maybe only
> under certain conditions.  I don't know.  But I would consider it
> invalid code.  You could fix it, by making the method signatures
> explicit.  You can of course write to gcc-bugs and see what they say.

In the first instance, I have to regard this as a compiler error because 
Apple's documentation on the Objective-C language at
http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC/3objc_language_overview/index.html
says the following under 'Defining a Class, "If a return or argument type 
isn’t explicitly declared, it’s assumed to be the default type for methods 
and messages—an id ."
An appropriate fix is another matter.  If what they have done helps speed, 
it may be better to change the documentation and add a warning to the 
compiler.

Many thanks to David for his excellent analysis.  I will report the 
behaviour to Apple.

Bill Northcott