> There's also usually a huge amount of overhead associated with C++
> exceptions, probably not a good idea for a Linux driver. Furthermore the
> simpliar method of checking the returned value(s) of functions is also
> easier to understand, read, and debug.
A huge amount compared to what? C++ exception handling is not just a fancy
replacement for checking return values. It allows an expressiveness and more
flexible flow of control within the code that may have to deal with that
situation. Used properly, exception handling should result in little or not
overhead compared to the explicitly coded option and sometimes can result in
less overhead. I've seen this happen in several situations when a well
organized exception handling policy was present. Lots of code that had to check
for error conditions simply went away. The best part is that most of the
overhead never had to be paid unless an exception actually did occur. My code
was smaller and faster as a result. Obviously I completely disagree with your
last sentence.
Now... what Alan says about the difficulty of supporting it within the
kernel may very well be the case - I don't know. That said, its time to start
considering the future. C++ cannot be ignored by the kernel forever. The
language just offers too much over plain C and was designed specifically with
large-scale systems programming in mind. The biggest limitation to full
adoption of C++ that I've seen is the whole ABI/method call convention/name
mangling fiasco which I feel really should have been addressed by the ANSI
committee (at least guidelines and suggestions for future standardization).
Since the egcs team has started reworking their code for an upcoming "de-facto
standard", it wouldn't surprise me if more compiler vendors saw the need to at
least support this as an option. At that point even public interfaces into the
kernel could be class method calls.
Until then, its time to start considering getting the kernel's code
buildable by g++ a little at a time. Just using it as a "better C" rather than
bringing all its features in at once would make for a cleaner system and extend
the life of the code by preventing cod rot. I know that this was attempted
briefly a while back (with disastrous results) but the kernel was really out of
ANSI spec then and the C++ compilers were not really there. How about
evaluating this as a feature for release 2.3?
regards,
Ben Scherrey
PS: I can just feel the cringing from the "C bigots" right now... sorry guys -
I really don't mean to stomp your turf!
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