how to use Pointer in JNA.

代码

int PTOsetApiOpt(int iOpt,void* lpValue,int iLen)

Parameters: iOpt: int
lpData: address from which data should be read.
iLen: length of data
returns int values : 0 as success or -1 as failure.

IN C

int PTOsetApiOpt(int iOpt,void* lpValue,int iLen)
 

Parameters: iOpt: int
lpData: address from which data should be read.
iLen: length of data
returns int values : 0 as success or -1 as failure.


Here's how i wrote it in Java..

void* lpValue can be any type. So in C it is expecting address of int value.
代码public MyTest{

 public interface MyLibrary extends Library {
   public int PTOsetApiOpt(int iOpt,Pointer lpValue,int iLen);

 }
 public static void main(String[] args) {
   MyLibrary myLib = (MyLibrary)MyLibrary.INSTANCE;
    IntByReference ir = new IntByReference(1);
    //got a result as 0 instead of -1.
    int result = myLib.PTOsetApiOpt(1, ir.getPointer() , ir.getPointer().SIZE);
 }