NDK conflict c/c++

Question

I'm working in an Android project with c++ files (NDK) but i have faced a problem native method not found , when i add the extern "C" { } i got new problem which is declaration of c function '..' conflicts with .h previous declaration here is my code

/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class com_marwen_parojet_ocr_2_PostPhot */

#ifndef _Included_com_marwen_parojet_ocr_2_PostPhot
#define _Included_com_marwen_parojet_ocr_2_PostPhot
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     com_marwen_parojet_ocr_2_PostPhot
 * Method:    Traiter
 * Signature: (Ljava/lang/String;)V
 */
JNIEXPORT void JNICALL Java_com_marwen_parojet_1ocr_12_PostPhot_Traiter
  (JNIEnv *, jclass, jstring);

#ifdef __cplusplus
}
#endif
#endif

this traitement_jni.h and the .cpp file is

#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv/cv.h>
#include "opencv2/ml/ml.hpp"
#include <android/log.h>
#include <jni.h>
#include "traitement_jni.h"
#include <stdlib.h>
extern "C" {
JNIEXPORT void JNICALL Java_com_marwen_parojet_1ocr_12_PostPhot_Traiter(JNIEnv* env,    jobject,jstring path){
  ...
 }
 }

Answer 1

It seems you are passing a jclass in the declaration but a jobject in the definition. If these two types aren't aliases for the same type, this doensn't work: you cannot overload extern "C" functions.

header file:

extern "C" {
    JNIEXPORT void JNICALL Java_com_marwen_parojet_1ocr_12_PostPhot_Traiter(
        JNIEnv *,
        jclass,    // <---- here
        jstring);
}

source file:

...
extern "C" {
    JNIEXPORT void JNICALL Java_com_marwen_parojet_1ocr_12_PostPhot_Traiter(
        JNIEnv* env,
        jobject,   // <---- here
        jstring path){
        ...
    }
}