cpp discrepancies

[Marc Espie]

Just to put things in context, I didn't try to find all those problems.
It's simply that OpenBSD features a lint that invokes cpp directly,
hence noticing that -undef was gone from the internal pre-processor, 
I proceeded to use the new cpp, and ran into ALL the problems I mentioned.

On Wed, Apr 28, 1999 at 12:28:10AM -0400, Zack Weinberg wrote:
> Specifically referring to cpp, the discrepancies you note are because
> cpp.texi/cpp.1 document the interface to the internal binary, and they
> don't get it exactly right either.  
That cpp.1 document that simply source cccp.1 doesn't help.

There should be a definite warning in the source that cccp is *internal*
and not meant to be used... having a man page for an internal program
is an error, imo, unless it is quite clearly labelled as internal.



> That `xcpp' executable is a
> "language-specific driver" which in this case means it behaves exactly
> like `gcc' except it has the -E switch automatically turned on.
> Therefore, you select the language with -x, and __GNUC__ is always
> defined, etc. etc. 

> I can fix all of the discrepancies you reported, but there's a big fat
> caveat: doing so will change the behavior of `gcc' as well, in the
> following ways:

> * -$ will be recognized and passed on to the preprocessor (not the
> compiler-proper, which doesn't understand it).
Probably not needed. Documentation upgrade is fine.
> * -lang-FOO will behave exactly like -xFOO.  People who have libraries
> named "libang-FOO.a" will lose.
Ditto
> * There will be a new switch, -no-gcc.  Passing this switch will cause
> the driver not to define __GNUC__ and __GNUC_MINOR__.
Definitely unneeded.   Documenting that even with -undef __GNUC__ and
__GNUC_MINOR__ are defined   is mandatory, on the other hand.  Nasty
surprise... this is the one that definitely bit me and took me an hour
to figure out...

> Are there any objections to these changes?  Do they require waiting
> for 1.3?

Documentation change is mostly fine by me...

Don't forget to either fix IN-FILE OUT-FILE, or fix the documentation
as well :)

-- 
	Marc Espie		
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