Re: an error from the expression: CLS_ISCLASS((Class)receiver) File: sendmsg.c Line 321

[Richard Frith-Macdonald]

On 13 Feb 2009, at 12:31, David Chisnall wrote:

> On 13 Feb 2009, at 08:30, Truls Becken wrote:
>
> > The other point I'd like to make is that importing <AppKit/AppKit.h>
> > in AppController.h would simplify things a bit. I guess it's  
> > debatable
> > whether this is better than declaring/importing only what is strictly
> > needed in the header and then import AppKit in the implementation
> > file, like you do now, but generally I think it's simpler to just
> > import AppKit in the controller header and be done with it. This  
> > would
> > replace the 5 classes you currently declare/import - a list which
> > would surely grow as you develop you application.
>
> The rationale for not #importing AppKit.h is that it is huge.  The  
> preprocessed header is over 700KB (just under 36,000 lines), which  
> means that the compiler has to build a parse tree that is likely to  
> be several MBs before it even gets to your program.
>
> This is worked around on OS X by using prefix headers.  These are  
> preprocessed and pre-parsed headers that are used automatically in  
> place of Cocoa.h (which, with GCC, has around a 30MB parse tree).   
> This is one of the main reasons why OS X programs use Cocoa.h rather  
> than AppKit.h and Foundation.h - you are only allowed one  
> precompiled header per program.
>
> I don't know if GNUstep make has support for precompiling Cocoa.h.   
> If not, it might be worth adding, since  it can reduce the memory  
> usage and processing time of a big build.

I know GNUstep-make supports precompiled headers, but I don't think it  
does Cocoa.h
It's not clear to me where Cocoa.h would be found/provided in the  
GNUstep packages.