Bug 23315 – Interface requires vtbl symbol betterC COM
Status
RESOLVED
Resolution
INVALID
Severity
normal
Priority
P1
Component
dmd
Product
D
Version
D2
Platform
All
OS
Windows
Creation time
2022-08-30T17:56:51Z
Last change time
2022-08-30T18:41:21Z
Assigned to
No Owner
Creator
Richard Cattermole
Comments
Comment #0 by alphaglosined — 2022-08-30T17:56:51Z
This came up due to somebody on Discord trying to use COM classes.
```d
interface Foo {
}
```
Will result in a linker error: ``testcombetterc.obj : error LNK2001: unresolved external symbol __D14TypeInfo_Class6__vtblZ``.
Command: ``dmd -betterC file.d``
This works with LDC and is how a COM interface is specified.
Comment #1 by snarwin+bugzilla — 2022-08-30T18:25:39Z
According to the language spec [1]:
> A COM interface is defined as one that derives from the interface core.stdc.winÂdows.com.IUnknown.
So, the example given in this issue is not a COM interface, and therefore should not be expected to work in BetterC (even if LDC allows it as a language extension).
[1] https://dlang.org/spec/interface.html#com-interfaces
Comment #2 by alphaglosined — 2022-08-30T18:41:21Z