Re: C++0x and Threads - a poor relation to Ada's tasking model?

[John McCabe <john@nospam.assen.demon.co.uk>]

On Thu, 13 Aug 2009 09:24:33 -0700 (PDT), REH <spamjunk@stny.rr.com>
wrote:

>On Aug 13, 9:51�am, John McCabe <j...@nospam.assen.demon.co.uk> wrote:

>> My point I guess is that some processors may have support for
>> facilities that map nicely on to Ada's exception handling, some
>> probably don't, but generalising in the way you have is not an
>> accurate representation (like there being no way to provide an
>> accurate representation of an object in C/C++ :-)
>
>You are making the assumption that hardware exceptions map to software
>exceptions.

It's not an assumption, it's a point; if an Ada compiler were to
choose not to use the features of the processor where those features
mapped closely to a feature of the language, then that's their choice.
I would hope that most compilers would assess whether the use of that
feature would be more effective than doing it "by hand" and choose
whichever is the most appropriate.

> An Ada run-time may do this (or it may not).

See above.

> C++ does not ( there is no such animal as C/C++).

Under the circumstances I use C/C++ to represent C and C++ as this
particular example is common to both; they both incorpoate
overwrapping semantics for operations on integer types (unlike Ada,
which provides a separate Modular type for that purpose).

>Ada has specific requirements for
>what happens when your Int16 overflows. C++ considered a signed
>integer overflow undefined behavior. The compiler is allowed to do
>anything it wants.

Oh dear.