JNI - UnsatisfiedLinkError

[Louis Denning]

Wasn't sure whether I should say this here or in the C/C++ forum, but here it is.

I'm programming a small game application for tutoring, where the GUI and main code are written in Java and the game logic implementation is written in some other language (in this case, C/C++) for the student to do. The implementation is mapped over via JNI and native methods.

I wrote a dummy implementation just to see if things would work. The native DLL library compiles fine, but Java does not seem to be able to link the method correctly.

The Java side:

package project3;
...
public class CGameLogic extends GameLogic {
    static {
        System.loadLibrary("logic");
        initializeNativeStuff();
    }
    ...
    private static native initializeNativeStuff(); // initializes stuff and caches things like jmethodIDs
    ...
}

The C++ side:
JNIEXPORT void JNICALL Java_project3_CGameLogic_initializeNativeStuff(PJNIEnv env, jclass cls) { // PJNIEnv is typedef'd to be JNIEnv* // initialization code }
An UnsatisfiedLinkError is thrown upon reaching the line that calls initializeNativeStuff. Might I have named something wrong?

[Rob Spoor]

Did you define PJNIEnv yourself? Because it's not part of the official JNI headers. And maybe that's the problem. Why don't you just let javah create the header file(s) for you? That would use JNIEnv * instead of PJNIEnv, but otherwise it would be the same.

[Louis Denning]

Changing PJNIEnv to JNIEnv* has no effect. They are the same type, as defined in a line I had forgotten to mention:
typedef JNIEnv* PJNIEnv;

EDIT:

Problem solved. Issue was wrong compiler flags and missing extern "C" in the function prototypes in header.