Creating *.dll in Visual Studio (using c++) for JNI

Question

Hi,
I'd like to ask, if anybody has experience how to make *.dll using Visual studio (2003) and use c++.
I make *.dll library in C ( in DEV-C++), it is no problem in C , but when I use C++, it doesnt work (it is the same in Visual studio)
I have the same code like in C ( the same header , and the "same" code - in dev-c++ it works well ) but when I try to create this same project using C++ it doesn work.
Visual studio throws exeption:
c:\Documents and Settings\patak\Dokumenty\Visual Studio Projects\jniknihovna\jniknihovna.cpp(13): error C2227: left of '->GetStringUTFChars' must point to class/struct/union
type is 'JNIEnv'
did you intend to use '.' instead?
c:\Documents and Settings\patak\Dokumenty\Visual Studio Projects\jniknihovna\jniknihovna.cpp(13): error C2819: type 'JNIEnv_' does not have an overloaded member 'operator ->'
Well does anybody have any idea how to solve this problem?

Answer 1

Well I think I use my compiler (dev-c++) corectly:
My codes :
*.h file (that is produced by javah)
/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class IntArray */
#ifndef IncludedIntArray
#define IncludedIntArray
#ifdef __cplusplus
extern "C" {
#endif
* Class: IntArray
* Method: sumArray
* Signature: ([I)I
JNIEXPORT jint JNICALL Java_pole_IntArray_sumArray
(JNIEnv *, jobject, jintArray);
#ifdef __cplusplus
#endif
#endif
And *.cpp
#include <jni.h>
#include <stdio.h>
#include "dll.h"
JNIEXPORT jint JNICALL
Java_pole_IntArray_sumArray(JNIEnv *env, jobject obj, jintArray arr)
jint buf[10];
jint i, sum = 0;
(*env)->GetIntArrayRegion(env, arr, 0, 10, buf);
for (i = 0; i < 10; i++) {
sum += buf;
return sum;
and in Java : private native int sumArray(int[] arr);
and again error : 10 C:\Dev-Cpp\dllmain.cpp base operand of `->' has non-pointer type `JNIEnv_'
(when I compile it as C library, it works , but I need to use C++ in other code, I can find only examples where only *.C is used )
Maybe here is an error, but I don't know how to solve this problem
Edited by: patakm1 on Apr 4, 2008 2:28 PM