https://issues.dlang.org/show_bug.cgi?id=21416
Issue ID: 21416 Summary: betterC mode program with C++ interface fails to link Product: D Version: D2 Hardware: x86_64 OS: Linux Status: NEW Severity: major Priority: P1 Component: dmd Assignee: nob...@puremagic.com Reporter: mob...@majumdar.org.uk import core.stdc.stdio : printf; //extern (C++) abstract class A { extern (C++) interface A { void sayHello(); } extern (C++) class B : A { override void sayHello() { printf("hello\n"); } } extern (C) void main() { scope b = new B; b.sayHello(); } Above fails to link with DMD, works with LDC. ~/Software/dmd2/linux/bin64/dmd -betterC interfaces.d /opt/rh/devtoolset-9/root/usr/libexec/gcc/x86_64-redhat-linux/9/ld: interfaces.o:(.data._D10interfaces1A11__InterfaceZ+0x0): undefined reference to `_D14TypeInfo_Class6__vtblZ' /opt/rh/devtoolset-9/root/usr/libexec/gcc/x86_64-redhat-linux/9/ld: interfaces.o:(.data._D10interfaces1B6__initZ+0x8): undefined reference to `_D10interfaces1B7__ClassZ' collect2: error: ld returned 1 exit status Error: linker exited with status 1 Tested on RHEL 7.9 DMD64 D Compiler v2.094.1 Replacing 'interface' with 'abstract class' appears to work in DMD, but this should not be necessary since interface is extern (C++). --