wouter van ooijen <wouter <at> voti.nl> writes:
> Maybe I should not react to this, but here I go...
> 
> >> exception handling => safety critical stuff
> > 
> > exception handling => race condition on small micro
> 
> a "race" condition is something very important indeed. 

A race appears when an exception is thrown and interrupts are on, if there is
more than one path to the exception handler and/or there are unguarded 
variables used by the throw mechanism. There is no inherent mechanism in the
try/throw/catch paradigm that guarantees it to work other than in a single
threaded environment. Either that or the task must be fully reentrant and that
requires a full stack frame of usually large size. Afaik no such thing exists 
on PICs (excepting on the largest ones).

> But I assume you meant "rare"? You did a lot of automibile, military,
> nuclear, and space projects? Ever programmed for ESA?

No, not at all. Are any PICs used in European missiles ? ;-)

> Ever programmed in a language that had exception handling, so you could
> appreciate it?

Yes, C++ and a little of others. But I did not feel like abusing it.
 
> > > templates => flexible libraries (reduces development costs)
> > 
> > flexible libraries with C++ calling conventions => huge 
> > memory and code overhead, high library porting and maintenance cost
> 
> I dunno about C++ calling conventions (multiple?), C++ can call by C
> convention if you want. 

C++ allows full virtual methods as you know. These need to be instantiated at
runtime i.e. a good part of the linker must be compiled into the program. And 
it has to be fully reentrant and thread-safe in an interrupted environment with
no memory protection. I don't even want to think about what that would look
like, although I'm sure it can be done.
 
> If you meanr 0.3 to 3.0 times *more*: bullocks. Take your C code, pass
> it through a C/C++ compiler in C++ mode and get the same assembly as in
> C mode. After that, see what could be done better with C++ constructs
> and start saving code.

I think that C++ excels precisely at what is 'forbidden' on micros due to
limited resources. Other than that, you are right. So basically you's use C++
without most convenient C++ features. Whatever is good for you.

Peter P.


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