On 6/12/20 8:54 PM, Walter Bright wrote:
> On 6/12/2020 5:17 PM, Andrei Alexandrescu wrote:
>> Not sure about that part - if linkage was static by means of using the
>> "static" keyword, multiple definitions may not be merged. (I may be
>> wrong, please correct me.) Consider:
>>
>> static inline int fun() {
>> static int x;
>> return ++x;
>> }
>>
>> In C++, each translation unit containing a definition of fun() will
>> have a distinct address for x. I don't see how the bodies of those
>> functions can be merged.
>
> They are not merged in D, for the simple reason that ModuleA.fun() and
> ModuleB.fun() will have different (mangled) names presented to the linker.
For D the question is if they are merged if the function is defined in a
.di file and imported in two other modules.
They are not 'merged', they just don't exist.
The problem I've repeated many times for D is that it doesn't emit the function ANYWHERE, and as such, you get a "undefined symbol" error. This is different than C++ where you would have gotten a "multiply defined symbol" error, but it's exactly the same problem for the exact same reason. It just manifests differently because C++ has .h files which naturally duplicates the code into each CU and D doesn't.