Re: signal handling and (structured) exception handling
Peter wrote:
I'm a little bit at loss, why the new C++ standard (C++0x) does not
include something like Windows structured exception handling.
Why should it be included in the Standard (new or old) when any
implementation is free to provide its own way of dealing with those?
I certainly prefer a C++ Exception to a signal, as the signal only
gives you the choice to terminate the process or mess around with
something as ugly as setjmp/longjmp.
Signals aren't really normative, are they?
And such signals/exceptions can sometimes not be avoided, e.g. in case
of the system runs out of disk space while writing into memory created
by memory mapped io from a sparse file.
Even in case of a null pointer access I would prefer to keep the
application running to be able to terminate it correctly.
Access to null pointer has undefined behaviour. The implementation is
free to define it. Some do. Some don't. There is no need to introduce
limitations by specifying what should happen.
> In this case
probably there is no need to try to execute the last verb again,
because it will run into the same null pointer access -- but at least
the destructors should work and the application can be terminated
correctly.
Whatever. If you're using a sophisticated operating system that allows
you to handle such a situation, be happy. You seem unhappy for some
reason. Do you want your Windows application with all the SEH stuff be
runable on MS-DOS? And you want the language to provide the means? I
do not see this as reasonable.
Another example is a floating point exception.
With exception handling I could avoid having to secure the code
against invalid inputs,
which also slows it down.
Slows it down? By how much? I've worked in systems that were set up to
handle FP exceptions and invalid pointer access... If you want it done
right, every damn function has to be littered with try/catch for those.
It is much, MUCH, easier to make sure you never try to calculate a
logarithm of a negative value or you never hang onto a dangling pointer.
A test for greater than 0 is so much quicker than setting everything
up for stack unwinding...
But you don't have to listen to me. If you see how Microsoft Structured
Exceptions can be brought into the language and implemented everywhere
the C++ compilers can exist, do write it up. I am sure folks in
comp.std.c++ will read your proposal with the same attention they give
every proposal.
V
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