Re: Limitations of Ada

[dewar@cs.nyu.edu (Robert Dewar)]

Klaus says

"There are no limitations, as long as you stay in the in the nice clean
ADA world.
If you go to the real dirty computer world, with all the C libraries
(Windows,X11,DCE, DB access .... ) you get a lot of limitations.
For example if your ADA is not based on pthreads you run into problems
with DCE."


Well of course if you are going to interface to the outside world, you
must make sure that your Ada compiler has the appropriate capabilities.
For example, if you want to interface to C, make sure that the systems
programming annex is supported.

Similarly, it is quite true that if you want to interface to an outside
threads package, then this has implications on the runtime. The statement
above is not quite correct, since DCE uses DCE threads, which are not
compatible with Pthreads (I assume Pthreads means Posix threads), since
they are based on Draft 4, rather than the final version (which was 
draft 10). However, the differences are small.

GNAT uses the DCE threads interface on a number of different machines, and
even on a machine where it uses pthreads (e.g. SGI Irix), it would be
quite easy to build a version based on DCE threads is this were a
requirement.