On Tue, Jul 3, 2012 at 9:38 AM, Stefan Behnel <stefan...@behnel.de> wrote:
> Dag Sverre Seljebotn, 03.07.2012 18:11:
>> On 07/03/2012 09:14 AM, Stefan Behnel wrote:
>>> I don't know what happens if a C++ exception is not being caught, but I
>>> guess it would simply crash the application. That's a bit more visible than
>>
>> Yep.
>>
>>> just printing a warning when a Python exception is being ignored due to a
>>> missing declaration. It's really unfortunate that our documentation didn't
>>> even mention the need for this, because it's not immediately obvious that
>>> Cython won't handle errors in "new", and testing for memory errors isn't
>>> quite what people commonly do in their test suites.
>>>
>>> Apart from that, I agree, users have to take care to properly declare the
>>> API they are using.
>>
>> Is there any time you do NOT want a "catch (...) {}" block? I can't see a
>> C++ exception propagating to Python-land doing anything useful ever.
>
> That would have been my intuition, too.If it's actually embedded, with the main driver in C++, one might want it to propagate up. >> So shouldn't we just make --cplus turn *all* external functions and methods >> (whether C-like or C++-like) into "except +"? (Or keep except+ for manual >> translation, but always have a catch(...)". >> >> Performance overhead is the only reason I can think of to not do this, >> although IIRC C++ catch blocks are only dealt with during stack unwinds and >> doesn't cost anything/much (?) when they're not triggered. >> >> "except -1" should then actually mean both; "except + except -1". So it's >> more a question of just adding catch(...) *everywhere*, than making "except >> +" the default. > > I have no idea if there is a performance impact, but if there isn't, always > catching all exceptions sounds like a reasonable thing to do. After all, we > have no support for catching C++ exceptions on user side. This is a bit like following every C call with "except *" (though the performance ratios are unclear). It just seems a lot to wrap every single line of a non-trivial C++ using function with try..catch blocks. I also don't think this would play well with Pynac (from Sage) which is a C++ library with Cython callbacks that may call back into the library and raise C++ exceptions (but that does feel a bit risky anyways). - Robert _______________________________________________ cython-devel mailing list cython-devel@python.org http://mail.python.org/mailman/listinfo/cython-devel
