How to compile D and C *.o files with GCC

Question

I'm trying to link D and C code using the DMD and GCC compiler. What I'v tried so far is using the DMD compiler to compile the source to *.o files, using the GCC compiler to compile the C source to *.o files, and using GCC to link the to create the binary.

However, the last step give me linker errors, giving me several "undefined symbol for architecture" errors

dmd ../src/Main.d -I../src -c
gcc -c ../ext/clibs.c
gcc *.o -o Main
Undefined symbols for architecture x86_64:
  "_D10TypeInfo_k6__initZ", referenced from:
      _D11TypeInfo_xk6__initZ in Main.o
  "_D12TypeInfo_Aya6__initZ", referenced from:
      _D13TypeInfo_xAya6__initZ in Main.o
  "_D14TypeInfo_Const6__vtblZ", referenced from:
      _D11TypeInfo_xk6__initZ in Main.o
      _D13TypeInfo_xAya6__initZ in Main.o
  "_D3std5stdio12__ModuleInfoZ", referenced from:
      _D4Main12__ModuleInfoZ in Main.o
  "__d_arraybounds", referenced from:
      _D6object7__arrayZ in Main.o
      _D4core4stdc6stdint7__arrayZ in Main.o
      _D3std8typecons7__arrayZ in Main.o
      _D3std6traits7__arrayZ in Main.o
      _D3std9typetuple7__arrayZ in Main.o
  "__d_assert", referenced from:
      _D6object8__assertFiZv in Main.o
      _D4core4stdc6stdint8__assertFiZv in Main.o
      _D3std8typecons8__assertFiZv in Main.o
      _D3std6traits8__assertFiZv in Main.o
      _D3std9typetuple8__assertFiZv in Main.o
  "__d_run_main", referenced from:
      _main in Main.o
  "__d_unittest", referenced from:
      _D6object15__unittest_failFiZv in Main.o
      _D4core4stdc6stdint15__unittest_failFiZv in Main.o
      _D3std8typecons15__unittest_failFiZv in Main.o
      _D3std6traits15__unittest_failFiZv in Main.o
      _D3std9typetuple15__unittest_failFiZv in Main.o

I'm guessing that the D *.o file refers to symbols in the STD D library. How do I include this when linking?

Answer 1

Answer I came up with, don't.
Simply use the DMD compiler for the last step

So, Instead of

dmd ../src/Main.d -I../src -c
gcc -c ../ext/clibs.c
gcc *.o -o Main

Simply

dmd ../src/Main.d -I../src -c
gcc -c ../ext/clibs.c
dmd *.o

You still have to write a D bridging header listing all the C function you want to use with the extern (C) syntax

For example

mycfile.c

int myfunction() {
    return 3;
}

mycbridge.d

extern (C) int myfunction();

And then include mycbridge.d in your D source.