array of devices - reopen about javacpp

[saudet]

uvcDevList should be declared as PointerPointer, no?

[lobsteroh]

correct. so i assume my java wrapper is off ...

public static native void uvc_free_device_list(@Cast("uvc_device**") @ByPtrPtr PointerPointer<?> uvcDevList, @Cast("uint8_t") byte unref_devices);

any suggestion on how i can fix it? whatever i try to change on it, it either won't compile into the jar or give me a compile error when i call it from ...

UVCController.uvc_free_device_list (uvcDevList, (byte)1);

am at the end of my limited wisdom ...

[saudet]

uvc_free_device_list() takes only a double pointer, so we don't need the @ByPtrPtr annotation. All that would be done automatically with the Parser BTW.

[lobsteroh]

thanks for the help, Samuel. I owe you quite a few drinks by now ... i am reviewing the final outcome of the issue for folks who end up here with similar questions.

the calls in the libuvc C library are ...

uvc_error_t uvc_get_device_list(uvc_context_t *ctx, uvc_device_t ***list) { .... }

and

void uvc_free_device_list(uvc_device_t **list, uint8_t unref_devices) { .... }

i am java wrapping them in the jlibuvc with ...

public static native int uvc_get_device_list(UVCContext ctx, @Cast("uvc_device***") @ByPtrPtr PointerPointer<?> uvcDevList);

and

public static native void uvc_free_device_list(@Cast("uvc_device**") PointerPointer<?> uvcDevList, @Cast("uint8_t") byte unref_devices);

i then make the calls do the work with the following code ...

public class UVCLoad { 
    public static void main(String... arg) throws InterruptedException {
        UVCDevice dev = new UVCController.UVCDevice();
        UVCContext ctx = new UVCController.UVCContext();
        UVCStreamCtrl sctrl = new UVCController.UVCStreamCtrl();
        System.out.println("Initialize : " + UVCController.uvc_init(ctx, null));

//      I could access the device directly with ...
//      System.out.println("Find Camera: " + UVCController.uvc_find_device(ctx, dev, 0x0, 0x0, null));
//      but in this example I get the list first, then pull the device at index 0 from it with ...
        PointerPointer<UVCDevice> uvcDevList = new PointerPointer<UVCDevice>();
        UVCController.uvc_get_device_list(ctx, uvcDevList);        
        dev = (UVCDevice) uvcDevList.get(UVCDevice.class, 0);

//      then I again free everything at the end.
        UVCController.uvc_free_device_list(uvcDevList,(byte)0);
        UVCController.uvc_unref_device(dev);
        UVCController.uvc_exit(ctx);
    }
}

i hope this helps ...

[saudet]

You're welcome! :)