Call .dll from Java

Hi,

I have followed the steps to create the header file then the .c file.

Also, downloaded the MinGW software to compile the file.

i am tryint to compile the file by providing the following command

E:\MinGW\bin>gcc -c -l"C:\Program Files\Java\jdk1.5.0_08\include" -l"C:\ProgramFiles\Java\jdk1.5.0_08\include\win32" - o "C:\calldll\MPmisDll.o" "C:\calldll\MPmisDll.c"

but i am getting the following exception.

C:/calldll/MPmisDll.c:1:17: jni.h: No such file or directory

In file included from C:/calldll/MPmisDll.c:2:

C:/calldll/MPmisDll.h:2:17: jni.h: No such file or directory

In file included from C:/calldll/MPmisDll.c:2:

C:/calldll/MPmisDll.h:15: syntax error before "void"

C:/calldll/MPmisDll.h:16: parse error before '*' token

C:/calldll/MPmisDll.h:16: warning: data definition has no type or storage class

C:/calldll/MPmisDll.c:6: syntax error before "void"

C:/calldll/MPmisDll.c:6: parse error before '*' token

Could you please tell me how to compile my .c file. So that i can create the .o file.

Thanks,

Arvind

arvind.m@mgl.coma at 2007-7-8 22:06:18 >

Hi bschauwejava,

For better understanding i will show some steps which i have done.

My Java File:

public native void encryptDll();

static {

System.load("C:/calldll/PPED.dll");

System.out.println("Loaded");

}

public static void main(String[] args) {

new MPmisDll().encryptDll();

}}

My header File by running the command javah -jni MPmisDll

/* DO NOT EDIT THIS FILE - it is machine generated */

#include <jni.h>

/* Header for class MPmisDll */

#ifndef _Included_MPmisDll

#define _Included_MPmisDll

#ifdef __cplusplus

extern "C" {

#endif

/*

* Class:MPmisDll

* Method:encryptDll

* Signature: ()V

*/

JNIEXPORT void JNICALL Java_MPmisDll_encryptDll

(JNIEnv *, jobject);

#ifdef __cplusplus

}

#endif

#endif

Then My C file :

#include <jni.h>

#include "MPmisDll.h"

#include <stdio.h>

#include <string.h>

JNIEXPORT void JNICALL Java_MPmisDll_encryptDll(JNIEnv *env, jobject obj)

{

printf("Hello world!\n");

return;

}

Then i am trying to compile this C file using the command:

C:\calldll>gcc -c -l"C:\Program Files\Java\jdk1.5.0_08\include" -l"C:\ProgramFiles\Java\jdk1.5.0_08\include\win32" -o "C:\calldll\MPmisDll.o" "C:\calldll\MPmisDll.c"

Then i got the error as i had posted earlier...So..Pelase let me know if their is any other steps i have missed out.

I have included the dll in same folder as well as Windows\System32.

Please let me know if i need to set anything in CLASSPATH or PATH in evironment varaible..

Thanks & Regards,

Arvind

arvind.m@mgl.coma at 2007-7-8 22:06:18 >

hi

try this commands..

I have did this in cygwin setup in the windows platform

javac -classpath . HelloWorld.java -->this command creates .class file..

javah -classpath . -jni HelloWorld -->this command creates C header file..

gcc -mno-cygwin -I /usr/include -Wl,--add-stdcall-alias -shared -o HelloWorld.dll HelloWorld.c --> this command creates " HelloWorld.dll "

java -cp . HelloWorld--> this command runs the java calling the function on C program through jni.

Message was edited by:

VaRadharajan

VaRadharajana at 2007-7-8 22:06:18 >