Calling DLL coded in D from Java

DlangLearner via Digitalmars-d-learn digitalmars-d-learn at puremagic.com
Tue Jun 16 15:47:03 PDT 2015


I'd like to know if it is possible to call an DLL coded in D from 
Java? I don't have any knowledge on DLL calling mechanism, so I 
am wondering if this is possible or any special procedure should 
be followed.

I indeed tried a small example but didn't succeed. First I 
created an DLL from the template in VisualD as below:

import std.c.windows.windows;
import core.sys.windows.dll;
import std.c.stdio;

__gshared HINSTANCE g_hInst;

extern(C)

export void dllprint() {
	printf("hello dll world\n");
}

extern (Windows)
BOOL DllMain(HINSTANCE hInstance, ULONG ulReason, LPVOID 
pvReserved)
{
     switch (ulReason)
     {
         case DLL_PROCESS_ATTACH:
             g_hInst = hInstance;
             dll_process_attach(hInstance, true);
             break;

         case DLL_PROCESS_DETACH:
             dll_process_detach(hInstance, true);
             break;

         case DLL_THREAD_ATTACH:
             dll_thread_attach(true, true);
             break;

         case DLL_THREAD_DETACH:
             dll_thread_detach(true, true);
             break;

         default:
             break;
     }
     return true;
}

and its DEF file:

LIBRARY      "z_dll.dll"
EXETYPE NT
SUBSYSTEM WINDOWS
CODE SHARED EXECUTE
DATA WRITE
EXPORTS
	dllprint

I am able to call the generated DLL from D. For calling from 
Java, I used JNA, and the code is:

public class TestDlangDLL {
	public interface DlangDLL extends Library {

		DlangDLL INSTANCE = (DlangDLL) Native.loadLibrary("C:\\z_dll",
				DlangDLL.class);

		void dllprint();
	}

	public static void main(String[] args) {
		DlangDLL dDLL = DlangDLL.INSTANCE;
		System.out.println(dDLL.toString()); //fine here
		dDLL.dllprint(); //crash on this call
	}
}

This test program is able to load the DLL, but unable to call the 
exported function dllprint.

Any guidance is appreciated.



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