Re: Is the Ada run-time required to detect out-of-memory conditions?

["Randy Brukardt" <randy@rrsoftware.com>]

"Wojtek Narczynski" <wojtek@power.com.pl> wrote in message
news:5ad0dd8a.0405210313.70f9339d@posting.google.com...
...
> > The program allocates memory in an infinite loop using "new" and the
> > default storage pool, and of course exhausts all available storage.
> > The issue is whether or not Storage_Error should be raised.  With
> > GNAT, no exception is raised; instead the program receives SIGKILL
> > (not even SIGSEGV) from Linux.
>
> I noticed, that if the program allocates memory in 6Kb chunks or
> larger, Storate_Error is raised. If the chunk size is 5Kb or less, the
> program only prints "Killed". In between I have not tested.
>
> Also, shouldn't cases like this one, as a rule, eventually become part
> of ACATS?

There is such an ACATS test. The original version just tried to allocate
memory until it was exhausted. In our case, this caused virtual memory
target machines to thrash badly (there was about one allocated item per
page). We ended up limiting the amount of heap memory to 8 Meg in order to
make that test pass -- which really was in no one's interest. We discussed
the issues and concluded that tests that try to exhaust memory are
meaningless on virtual memory systems.

That version was replaced by a newer one that (A) allocates larger chunks of
memory; and (B) only tries to allocate a limited amount of memory before
giving up. That preserves the test for the embedded systems that it is
meaningful for, and prevents the need to do senseless things like limit the
amount of memory that you can allocate.

                    Randy.