Experimenting with exporting symbols from a multi-platform C++ executable

vm.cpp

// Testing symbol visibility from a C++ executable
// file: vm.cpp
// revision: 09/29/2011 1:42:06 PM
//
// build via:
//   export demangled symbols (mingw): g++ -DRBX_API_EXPORT -o vm.exe vm.cpp
//   force export (mangled & demangled) symbols (*nix): g++ -o vm vm.cpp -Wl,-export-dynamic
//   forced (mangled & demangled) symbol export (mingw): g++ -o vm.exe vm.cpp -Wl,-export-all-symbols
//   export no symbols (mingw, *nix): g++ -o vm[.exe] vm.cpp
//
// verify exported symbols (mingw): objdump -p vm.exe | less
// verify exported symbols (*nix): objdump -T vm | less
//
// TODO
//   * verify link from DLL behavior on mingw and *nix
#include <iostream>
using namespace std;

#if defined(_WIN32)
#  if defined(RBX_API_EXPORT)
#    define RBX_API(type) extern "C" __declspec(dllexport) type
#  elif defined(RBX_API_IMPORT)
#    define RBX_API(type) extern "C" __declspec(dllimport) type
#  else
#    define RBX_API(type) extern "C" type
#  endif
#else // not _WIN32
/* TODO verify no need to do anything non-default like this for *nix
#  if __GNUC__ >= 4
#    if defined(RBX_API_EXPORT) || defined(RBX_API_IMPORT)
#      define RBX_API(type) extern "C" __attribute__((__visibility__("default"))) type
#    elif !defined(RBX_API_EXPORT) && !defined(RBX_API_IMPORT)
#      define RBX_API(type) extern "C" __attribute__((__visibility__("hidden"))) type
#    endif
#  else
#    define RBX_API(type) extern "C" type
#  endif
*/
#  define RBX_API(type) extern "C" type
#endif


namespace rubinius {
	namespace capi {

		RBX_API(void) capi_raise_runtime_error(const char* reason)
		{
			cout << "[RBX_API(void)] 'rubinius::capi::capi_rais_runtime_error' raising runtime error: " << reason << endl;
		}

		void capi_raise_backend()
		{
			cout << "'rubinius::capi::capi_raise_backend' internal raising impl" << endl;
		}
	}
}

RBX_API(int) rb_scan_args()
{
	cout << "[RBX_API(int)] non-namespaced 'rb_scan_args' says hi" << endl;
	return 0;
}

RBX_API(void) rb_str_new()
{
	cout << "[RBX_API(void)] non-namespaced 'rb_str_new' says hi" << endl;
}

namespace {
	void foo()
	{
		cout << "private namespaced 'foo' says hi" << endl;
	}
}

void bar()
{
	cout << "non-namespaced, non-static 'bar' says hi" << endl;
}

static void baz()
{
	cout << "non-namespaced, static 'baz' says hi" << endl;
}


int main(int argc, char **argv)
{
	foo();
	bar();
	baz();

	rb_scan_args();
	rb_str_new();

	rubinius::capi::capi_raise_runtime_error("uh-oh");
	rubinius::capi::capi_raise_backend();

	return 0;
}