Incomprehensible compiler errors

[Walter Bright]

On 7/30/2012 9:31 AM, Stuart wrote:
> I'm trying to write an actual program in D, but no matter what I do I get stupid
> errors that mean nothing to me. (Reminds me of C++)
>
>     Error 42: Symbol Undefined
>     _D8infinity8standard7runtime4IApp4IApp11__InterfaceZ

This means module infinity, and standard.runtime.Iapp ...


> Huh? This usually happens if I omit the module statement at the top of EVERY
> DAMN FILE (why???) but in this case I haven't omitted it, yet I'm still getting
> the error.

It's likely that you aren't presenting the compiled version of inifinity.obj to 
the linker.


> Also, I get the following error:
>
>     Error 42: Symbol Undefined
>     _D3dfl8internal6winapi12__ModuleInfoZ
>
> The code producing this second error is:
>
>      int Run() {
>          import core.sys.windows.windows;
>          import dfl.internal.winapi;
>          MSG msg;
>          while (GetMessageA(&msg, null, 0, 0)) {
>              TranslateMessage(&msg);
>              DispatchMessageA(&msg);
>              if (msg.hwnd && !IsWindow(msg.hwnd)) break;
>          }
>          return 0;
>      }
>
> What the HELL is this "ModuleInfo", why is it necessary, why is it always
> missing when a "module" statement is not present, and why is it missing NOW?

A ModuleInfo is generated for each compiled module and inserted into its 
corresponding .obj file. If the linker cannot find it, then it is likely that 
you need to specify that .obj on the link command.