C/C++ Question [Solved] B4R::Array from double[]

[Daestrum]

I think I have exhausted all the ways I can think of doing this. I need to return an Array to B4R from a library wrapper routine.

The current code:

    B4R::Array* rJson::getArray(B4R::B4RString* key,B4R::Object* o)
    {
        JsonArray data = obj[(char*)key->data].as<JsonArray>();
        B4R::Array* arr = (B4R::Array*)o->data.PointerField;
        double d[(int)arr->length];
        int a = 0;
        for(JsonVariant v : data) {
            d[a++] = v.as<double>();
            ::Serial.printf("%3.6f \r\n",d[a-1]);
        }
        arr->wrap(d,(unsigned int)2);
        o = (B4R::Object*)arr;
        return arr;
    }

The serial.print confirms that d[] does contain the values I want.

in the B4R code its called by

dim d[2] As Double
Json.getArray("data",d)
' I also tried  d = Json.getArray("data",d)  with the same results

logging d(0) and d(1) always returns 2 and 3.1309 even though the 'data' is 48.756080 and 2.302038

 

[Erel]

Your code cannot work as you are creating an array on the stack. The memory is released when method ends.

It will be much simpler, and will require less memory, to pass the array to this method and fill it.

 

[Daestrum]

Sorted thank you. I had passed the array to the function, but didn't know how to add items to it.

Final working code in case anyone else needs to do similar.

    B4R::Array* rJson::getArray(B4R::B4RString* key,B4R::Object* o)
    {
        JsonArray data = obj[(char*)key->data].as<JsonArray>();
        B4R::Array* arr = (B4R::Array*)B4R::Object::toPointer(o);
        int a = 0;
        for(JsonVariant v : data) {
            ((Double*)arr->getData((UInt) (a++)))[B4R::Array::staticIndex] = (double)v.as<double>();
        }
        o = (B4R::Object*)arr;
        return arr;
    }