Tobias Schwinger <tschwinger@neoscientists.org> writes:
David Abrahams wrote:
Tobias Schwinger <tschwinger@neoscientists.org> writes:
David Abrahams wrote:
Client code that wants to work whether exceptions are turned on or not also requires #ifdefs, no matter what you do with the interface to this particular library.
To ensure we understand each other correctly: a non-throwing interface can always be used, regardless whether exceptions are available or not, right?
Whoops. OK, that's right.
A non-throwing interface may even be attractive when generally using exceptions in case you would enclose the initialization with a try-catch block, anyway. In the particular case of this library the initialization is likely to happen at application start-up, so it isn't too difficult to imagine cases for both the RAII and the success-return approach to come handy.
If you get a failure at application start-up and you *don't* throw an exception, what do you hope your application will do? Continue without shared memory?
I just noticed Boost.Build supports optional exception handling (at least for some compilers), so the second point in my previous post probably isn't too much of an issue. Still -- I can't help but find it cleaner to have another class for RAII which simply won't be availible if BOOST_NO_EXCEPTIONS is defined rather than to have a class interface shape-shift based on compiler settings or deficiencies.
Great, that was the 2nd of my 3 suggestions for addressing this problem.
No docmatic about exceptions from my side in any way; I believe, however, it's a good thing to have (at least some) libraries that allow to turn exceptions off -- it adds to the value of Boost because it welcomes users working with resource-critical execution environments
Absolutely. No argument from me.
and AFAIK it's impossible to implement zero-overhead stack unwinding (you're the exception expert, so please correct me if I'm wrong).
If by "zero-overhead stack unwinding" you mean exception handling that has no speed cost unless an exception is thrown, then consider yourself corrected.
BTW. I hope we're not in a flame-war ;-), are we? I also hope it doesn't seem like it...
No, I don't think we are. -- Dave Abrahams Boost Consulting www.boost-consulting.com