Re: Mysterious crash in NSRunLoop, using libobjc2 on Linux

[David Chisnall]

> On 11 Dec 2017, at 17:09, Lobron, David <dlobron@akamai.com> wrote:
> 
> 
>>>> Just use @try and @catch.  If you can find a smallish test case, please 
>>>> file a bug on GitHub and I’ll take a look.  Ideally, a test case shouldn’t 
>>>> depend on anything other than libobjc2 - take a look at the existing EH 
>>>> tests and see if you can make a similar one that shows the issue.
>>> 
>>> I've been trying combinations of C++ and ObjC exceptions in a .mm file, and 
>>> so far I haven't been able to reproduce the abort behavior.  I've attached 
>>> my latest code, which throws ObjC and C++ exceptions from C++ and ObjC 
>>> classes, and catches them.  Please let me know if you can think of any 
>>> variations I haven't tried here.  
>>> 
>> 
>> If the failure is what I suspect that it is, then it’s a problem caused by 
>> mixing C++ and Objective-C exception unwinding, so it won’t be possible to 
>> reproduce in a single file.  You will need to throw an exception from 
>> Objective-C++ and have it pass through stack frames from an Objective-C 
>> compilation unit that includes an @finally block that runs some code, and 
>> then be caught in an Objective-C++ compilation unit.  
> 
> Ah, got it.  I will try this.  
> 
> Would separate .o files linked into a single binary be sufficient for 
> counting as separate compilation units?

Yup, that’s fine.

David