Problems with a custom constant string class

[Vincent Geddes]

Hi!

I am experimenting with Objective-C, and I am trying to create some
custom string classes.

The problem is that the gcc '-fconstant-string-class' option only seems
to allow custom classes which subclass `Object' (in the GNU runtime).
gcc keeps on giving me the error `interface 'GooConstantString' does not
have valid constant string layout' if I subclass anything other than
`Object'. 

Is there any way I can have a constant string class that can subclass
anything other than `Object'? 


Interfaces:
@interface GooObject
...
@end
@interface GooString : GooObject
...
@end
@interface GooConstantString : GooString
{
  Class isa;
  char *c_string;
  unsigned int len;
}
@end

gcc -v:
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --enable-languages=c,c
++,fortran,objc,obj-c++,treelang --prefix=/usr --enable-shared
--with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --enable-nls --program-suffix=-4.1
--enable-__cxa_atexit --enable-clocale=gnu --enable-libstdcxx-debug
--enable-mpfr --enable-checking=release x86_64-linux-gnu
Thread model: posix
gcc version 4.1.2 (Ubuntu 4.1.2-0ubuntu4)


regards,
Vincent