Re: Is 3.15p -still- the latest GNAT 'p' release?

[Mark H Johnson <Mark_H_Johnson@raytheon.com>]

Marin David Condic wrote:
> You could 
> probably freeze 3.15p and never make another release and still have a 
> perfectly usable product.

Actually on Linux, that is not quite true. I have a very large system 
implemented on GNAT / Linux (still 3.14a, but compatible with 3.17w) but 
someday, we have to step up beyond Red Hat 7.3 to something a little 
more modern. At that point, we have the pthread compatibility issue to 
deal with. We have the following options at that point:

  - step up to 3.16 or later to stay with the older backend
  - step up to 5.02 or later to use the new backend

Both of these official compiler releases have RH <9 and RH >=9 versions 
available.

I don't expect the first option to be a good long term strategy because 
I expect ACT to drop support for the 3.xx compilers within a year or so. 
They haven't said that directly but the following statement in the 5.02a 
release notification appears to imply that...
   "The 5.02a release completes the transition from GNAT3 to GNAT5 for
most of the GNAT Pro configurations."

The second option is also not quite as clean as we would like. The 
backend in 5.xx appears to do more aggressive optimization and we have 
some broken code to fix (it appears we need to add some more pragmas for 
aliasing or volatile). It is an annoyance at this point (since we 
obviously have working code / compiler) but time will be needed to make 
the fixes.

Yes - I am aware of the environment variable work around, but I don't 
see that as a good long term strategy either.
   --Mark