如何使用JNA从结构中获取Structure.ByReference？

Question

I do have a object of Structure in my java code. But the Jar generated using JNAerator expects Structure.ByReference as a data type. Is there any method in jna or code snippet to convert Structure object into Structure.ByReference object?

Answer 1

Generally, you don't need to explicitly specify Structure.ByReference when passing parameters. If it's a parameter, you can drop the .ByReference from the signature and it'll work just fine.

If it's a field within a structure, then JNA interprets Structure as by value, in which case you would need to provide the .ByReference explicitly.

This is one way to do it.

class MyStructure extends Structure {
    class ByReference extends MyStructure implements Structure.ByReference {
        public ByReference() { }
        public Byreference(Pointer p) { super(p); read(); }
    }
    public MyStructure() { }
    public MyStructure(Pointer p) { super(p); read(); }
}

MyStructure s;
// ...
MyStructure.ByReference ref = new MyStructure.ByReference(s.getPointer());