How to convert String value to Pointer<Byte> (Java, JNAerator)?

Question

I have converted .dll library to JAR by using JNAerator. Now I need to call OpenTCPIPPort_V method which looks like this: public static short OpenTCPIPPort_V(Pointer<Byte > tcpPort, Pointer<Byte > IPAddr)

How to pass two string values to this method?

Answer 1

There is a function from a String class called getBytes. Here is an example:

String example = "example, string";
byte[] bytes = example.getBytes();

What you need now is to put those byte[] values into your's Pointer. I think you can handle now.

Answer 2

I found solution. This is method Pointer<Byte> org.bridj.Pointer.pointerToCString(String string)

Answer 3

I tried pointerToCString for the TekVisa DLL (DLL to control measurement instruments from Tektronix) which did not work for opening an instrument session. The second answer in this thread is better but misses a detail: The byte array has to be terminated with a 0. My code below works. (The instrument variable is of type String and contains the instrument string, for instance "TCPIP::::INSTR".)

Interestingly, pointerToCString works when sending a command to the instrument, for instance viWrite("*IDN?").

  Pointer<Byte> pViString = Pointer.allocateBytes(instrument.length() + 1);
  byte[] instrumentBytes = instrument.getBytes();
  pViString.setBytes(instrumentBytes);
  pViString.setByteAtIndex(instrument.length(), (byte) 0);