Re: [PATCH] DEFAULT_SIGNED_BITFIELDS Macro

[Jeffrey A Law <law at cygnus dot com>]

  In message <19990603081217R.mitchell@codesourcery.com>you write:
  > That's a reasonable argument.  But there's clearly a tradeoff:
  > 
  >   o On the one hand, we will break the ABI on DG/UX.  Some programs
  >     that ran correctly on DG/UX will have to be modified, or have
  >     their Makefiles altered.
Right.  And this is bad.


  >   o On the other hand, supposedly portable GNU CC programs (i.e., 
  >     programs adhering to documented aspects of GNU CC, with the
  >     expectation that they will be portable to other platforms 
  >     running GNU CC) will have to be modified, or have their
  >     Makefiles altered.
No.  Because a portable program would not depend on the signedness of a
bitfield.  If it did, then it should be specifying the signedness it desires
explicitly, either via flag or a signed/unsigned qualifier on the bitfield
itself.

  > I'd still prefer to have GNU CC adhere to its own long-standing
  > documented behavior, but I'm not a DG/UX expert.
Even if the long-standing documented behavior is due to someone not actually
understanding ABI issues?

jeff