JNA Pointer class: How to set Pointer object to point to another class?

Question

I am trying to create a single Pointer object using the JNA library and set it to "point" to an object of a custom data type defined.

Can someone please explain how to do this?

CustomType ctype = new CustomType();
Pointer pointer = new Pointer(ctype);

This does not work. I have tried searching and googling but none of the questions I found have shown what I need.

How do you expect your native code to use the pointer you give it? — technomage
– technomage, Commented Mar 12, 2015 at 3:05
It should write something into the custom data type. A set of numbers which can be translated to status codes. — isaric
– isaric, Commented Mar 12, 2015 at 7:57
This might be answering my own question but it seems I should define the custom data type as a sublase of structure. — isaric
– isaric, Commented Mar 12, 2015 at 8:26

technomage · Accepted Answer · 2015-03-12 10:31:53Z

1

Use a subclass of com.sun.jna.Structure and pass that object directly to your mapped method. JNA will automatically take care of synchronizing the native data and pass a pointer to that data to the native method.

Refer to JNA's documentation on how to use Structures and the FAQ.

answered Mar 12, 2015 at 10:31

technomage

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1 Comment

isaric Over a year ago

I'm trying but I can't instantiate an object of this new class for some reason. I made a separate question here if you have any thoughts: stackoverflow.com/questions/29010272/…

isaric · Accepted Answer · 2015-03-12 09:16:31Z

0

Okay, so as I stated in the comment, the sollution was to make the custom data type a subclass of JNA structure which has a getPointer() method.

answered Mar 12, 2015 at 9:16

isaric

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