CODEWITHSUNDEEP
javaandroidandroid-ndkjava-native-interface
Tank2005
Tank2005

Reputation: 909

About the array which allocated in JNI

I wrote a function allocating Java array in Android JNI. However, if this function is called continuously from Java, an error[*Fatal signal 11 (SIGSEGV)] will occur.

C++

static jbyteArray buffer = NULL;
static int cbuflen = 0;
jbyteArray Java_com_sample_buffer_Buffer_updateBuffer(JNIEnv* env, jobject thiz, jlong handle, jint buflen)
{
    if(buflen > cbuflen){
        if(buffer != NULL) env->DeleteLocalRef(buffer);
        buffer = env->NewByteArray(buflen);
        cbuflen = buflen;
    }
    return buffer;
}

Java

byte[] buf = conv.updateBuffer(buflen);

Should not I use this way? Or is there some measures?

Upvotes: 3

Views: 2446

Answers (1)

Mārtiņš Možeiko
Mārtiņš Možeiko

Reputation: 12927

If you want to keep jobject (like jbyteArray) between JNI calls you need to make it a GlobalRef:

jbyteArray temp_buffer = env->NewByteArray(buflen);
buffer = (jbyteArray)env->NewGlobalRef(temp_buffer);

Only then remeber to delete object to free memory:

env->DeleteGlobalRef(buffer);

Upvotes: 4

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