extern(C++) multiple inheritence

[Manu via Digitalmars-d]

On 26 January 2016 at 15:11, Walter Bright via Digitalmars-d
<digitalmars-d at puremagic.com> wrote:
> On 1/25/2016 9:02 PM, Manu via Digitalmars-d wrote:
>>
>> On 24 January 2016 at 20:40, Walter Bright via Digitalmars-d
>> <digitalmars-d at puremagic.com> wrote:
>>>
>>> On 1/22/2016 5:46 PM, Manu via Digitalmars-d wrote:
>>>>
>>>>
>>>> I brought a work laptop home this weekend in anticipation ;)
>>>
>>>
>>>
>>> Here ya go:
>>>
>>>    https://github.com/D-Programming-Language/dmd/pull/5364
>>>
>>> Be wary of:
>>>
>>>    https://issues.dlang.org/show_bug.cgi?id=15589
>>>
>>> and use the workaround as necessary. This is lower priority, so I won't
>>> be
>>> dealing with it for a bit.
>>
>>
>> Next blocker: https://issues.dlang.org/show_bug.cgi?id=15610
>>
>> C++ methods with multiple-inheritence expect that 'this' is a pointer
>> to the base class that introduced the function.
>> When using C++ 'interface's, which C++ just treats like normal
>> multiple-inheritence, C++ expects that the 'this' pointer is adjusted
>> to the offset of the interface's vtable.
>>
>> If I have:
>> extern(C++) interface Interface { voif f(); }
>> extern(C++) class C : Base, Interface
>> {
>>    void f();
>> }
>>
>> Calling c.f(), D is passing 'this' unaltered, but C++ expects 'this'
>> is a pointer to 'Interface', and then it crashes accessing members at
>> incorrect offsets.
>>
>
> The PR 5364 does this. (And only Microsoft Win64 has this effect.)

Oh okay. I thought that PR was about correctly locating the vtable and
function offsets. I'll wait till that's merged.