Re: Gnat on OpenVMS

[Robert Dewar <dewar@gnat.com>]

In article <1999May19.172621.1@eisner>,
  Kilgallen@eisner.decus.org.nospam wrote:
> In article <7hv83e$t2o$1@front4.grolier.fr>, "Thierry
Lelegard" <lelegard@club-internet.fr> writes:

> I have never used GDB, but the potential problem
> that concerns me is debugging a multilingual program.
> If one calls from Ada into
> Bliss or PL/I, I presume GDB is not going to step through that
> with beautiful debugging ability in both the Ada and non-Ada
> parts.

That's a legitimate concern. I think we can all agree that
it would have been desirable to be fully integrated with
the old VMS debugger, but unfortunately this would have
required significant work (to accomodate Ada 95) and that
was not about to happen.

GDB does of course handle multi-lingual debugging well if
all languages are generating a debugging format that GDB
understands.

As Larry says, one solution, at least in the C case, is to
debug using GNU C, and then switch later if necessary.

Another approach, perhaps the best for the long term, is to
teach the other Digital compilers to be GDB compatible. This
is by no means impossible. It could be done on the GDB side
by teaching GDB about the DEC-specific format used now, or
it could be done on the compiler side by having the DEC
compilers generate one of the industry standard formats.

I think this approach may make better sense in the long run,
since we will see major development in GDB over the next
couple of years, addressing such features as multi-processing
and scalability, since there seems to be a significant
movement in the direction of adopting GDB from several
hardware manufacturers, and of course the GNU-Linux work
will result in continuing improvement of GDB.

I suspect this was at least part of the thinking on Digital's
part in requiring the use of GDB as the debugging solution
for GNAT/VMS.

Robert Dewar
Ada Core Technologies


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