Loading Win32/64 DLLs "manually" without LoadLibrary()

// This DLL has been compiled/linked without the standard library.
//
// Since there is no standard library some C/C++ features don't work.
// Several features (like debug runtime checks) are turned off on the "Code Generation"
// page since these features require the support of the default runtime library.
// The lack of the std lib is more painful in C++ than in C (for example static variable init
// and deinit doesn't work), no default new/delete operator, etc... You can use a mini
// standard lib to provide these.
// Still, being able to use C/C++ instead of assembly to write relocatable code patches is cool!!!
#include <windows.h>
#include <stdarg.h>
#include "TestDll.h"


// Since we have no standard C/C++ library just pure WinAPI...
int printf(const char* format, ...)
{
	int len, max_len;
	DWORD written;
	char buf[0x100];
	va_list args;

	va_start(args, format);
	len = wvsprintfA(buf, format, args);
	va_end(args);

	max_len = (int)sizeof(buf)-1;
	len = len < max_len ? len : max_len;
	buf[len] = 0;

	WriteConsoleA(GetStdHandle(STD_OUTPUT_HANDLE), buf, (DWORD)len, &written, NULL);
	return len;
}

int AddNumbers(int a, int b)
{
	printf("DLL: AddNumbers(%d, %d)\n", a, b);
	return a + b;
}

void MyMessageBox(const char* message)
{
	printf("DLL: MyMessageBox(\"%s\")\n", message);
	MessageBoxA(NULL, message, "DLL MessageBox!", MB_OK);
}

DLLInterface g_Interface =
{
	AddNumbers,
	MyMessageBox
};

__declspec(dllexport) const DLLInterface* GetDLLInterface()
{
	return &g_Interface;
}

// If you don't need a DllMain then you can delete this function and then use the /NOENTRY linker option.
BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
{
	// With manual DLL loading you can not use DLL_THREAD_ATTACH and DLL_THREAD_DETACH.
	switch (fdwReason)
	{
	case DLL_PROCESS_ATTACH:
		printf("DLL: DLL_PROCESS_ATTACH\n");
		// TODO
		break;
	case DLL_PROCESS_DETACH:
		printf("DLL: DLL_PROCESS_DETACH\n");
		// TODO
		break;
	default:
		break;
	}
	return TRUE;
}