Styjun

I don't know how to map it correctly.

C method

void* function(char* h, int p, void (*vrecv)(void* , uint8_t *, size_t ), 
 void* d, const char* n, uint8_t p8, uint16_t p16, uint32_t p32);

JNI wrapper method

JNIEXPORT jstring JNICALL
Java_com_example_hellojni_HelloJni_function( JNIEnv* env, jobject thiz,
 blah-blah ) 
 return blah-blah;

Java method

public native void function();

There are few examples with
access through an java array, calling with method CallVoidMethod or with GetMethodId, but I don't understand them. It's hard to see the idea through java method, c/c++ func and jni wrapped method.

Tutorial for JNI API

Google Android NDK / JNI Samples

This is example works fine:

HelloJni.java file.

JNIEXPORT jint JNICALL Java_com_example_hellojni_HelloJni_example(JNIEnv*env,
 jobject obj) 
 return (jint) example();

hello-jni.c file.

void* run_thread(void* num) 
 int* temp = (int*) num;

 while(++(*temp) < 777);

 printf("Hello world! C Style! From pthread and Android NDK(JNI).n");

 return NULL;


int example() 
 int f = 0;
 pthread_t pipe;

 if(pthread_create(&pipe, NULL, run_thread, &x)) 
 fprintf(stderr, "Error creating threadn");
 return 1;
 

 sleep(1);

 printf("before x: %dn", x);

 /* wait for the second thread to finish */
 if(pthread_join(pipe, NULL)) 
 fprintf(stderr, "Error joining threadn");
 return 2;
 

 printf("after x: %dn", x);

 return x;

How to access c data structures?

public native void example1(/**/);

How to call elements of typedef struct?

What next step for void* pointer (a correct representation with long cause 64 bit)?

public native void example2(long cl);
public native void example3(/**/);
public native void example4(/**/);

void* example1(char* h, int p, void (*vr)(void* , uint8_t *, size_t ), void* vdt,
void (*ar)(void* , uint8_t *, size_t ), void* adt);
void example2(void* cl);
void example3(void* cl, uint8_t is_p, uint8_t num, const char* name, uint8_t btype, uint8_t v, uint8_t prod, uint16_t opts);
void example4(void* cl, uint8_t num, uint16_t t, uint32_t c, uint32_t v);

JNIEXPORT void JNICALL Java_com_example_hellojni_HelloJni_example1 (JNIEnv* env, jobject obj, jchar* h, jint p, jlong vr, jlong vdt, jlong ar, jlong adt) 
 const char *str= (*env)->GetStringUTFChars(env,h,0);

 example1(str, p, vr, vdt, ar, adt);

JNIEXPORT void JNICALL Java_com_example_hellojni_HelloJni_example2 (JNIEnv* env, jobject obj, jlong cl) 
 example2(cl);

JNIEXPORT void JNICALL Java_com_example_hellojni_HelloJni_example3 (JNIEnv* env, jobject obj, jlong cl, uint8_t is_p, uint8_t num,
 jstring name, uint8_t btype, uint8_t v, uint8_t prod, uint16_t opts) 

 const char *str= (*env)->GetStringUTFChars(env,name,0);

 example3(cl, (jshort)is_p, num, str, (jshort)btype, (jshort)v, (jshort)prod, (jshort)opts);

JNIEXPORT void JNICALL Java_com_example_hellojni_HelloJni_example4 (JNIEnv* env, jobject obj, jlong cl, uint8_t num, uint16_t t, uint32_t c, uint32_t v) 
 example4(cl, (jshort)num, (jshort) t, (jlong)(unsigned long long) c, (jlong)(unsigned long long) v);