Question

I’ve set up a trivial test to link D code with C, but I’m running into linker problems.

// Compiled with "gcc -c CTest.c."

void SayHello()
{
    printf("%s", "Hello, world!");
}

// Compiled with "dmd DTest.d CTest.o."

extern (C) void SayHello();

void main()
{
    SayHello();
}

ld spits out:

ld: warning: in CTest.o, file was built for unsupported file format which is not the architecture being linked (i386)
Undefined symbols:
  "_SayHello", referenced from:
    __Dmain in DTest.o
ld: symbol(s) not found

I’ve tried manually specifying CTest.c‘s architecture with -m32 -march=i386, but that gives me a bus error at runtime. I’ve never gotten a bus error before, so that just goes right over my head.

What am I doing incorrectly?

Answer 1

I’m going to assume you have the 32bit dmd installed. Your initial attempt to change gcc seems correct, maybe try dropping the -march option. Otherwise try the D compilation with -m64 then try -m32 if it didn’t work.

Yes dmd can link with GCC generated object files targeted at the Linux ELF format, and I believe MacOS/BSD? March format. Windows DMD produces OMF while COFF is more popular now.