Android NDK - try catch with NoMemoryError

Question

I have block of code, which in Android NDK allocates huge ammounts of memory. Last what I need is to use try - catch block for possibility, there might be NoMemoryError. Do you know how to write it in native SDK?

I need to implement same functionality as this:

        for(int i=1;i<50;i++){
        try{
            int[] mega =new int[i*1024*1024];//1MB

        }catch (OutOfMemoryError e) {
            usedMemory= (Runtime.getRuntime().totalMemory()-Runtime.getRuntime().freeMemory())/new Float(1048576.0);
            usedText=usedMemory+" MB";
            tw.setText(usedText);          
            break;
        }
    }

Answer 1

In your JNI function you can throw a java exception using the follow snippet. When compiling the native code make sure RTTI and exceptions are enabled.

try {
  int *mega = new int[1024 * 1024];
} catch (std:: bad_alloc &e) {
  jclass clazz = jenv->FindClass("java/lang/OutOfMemoryError");
  jenv->ThrowNew(clazz, e.what());
}

In Java you can simply catch the OutOfMemoryError.

try {
  // Make JNI call
} catch (OutOfMemoryError e) {
  //handle error
}

Answer 2

Android is not very friendly to C++ exceptions (you must link with a special version of the C++ library provided by Android to have exceptions). Maybe you should use malloc() and check its return value to see if memory allocation was OK?