Search code examples
javac++java-native-interfacejna

Mapping of types: wchar_t*& and char*& in JNA

My client gave me dll with a couple of functions. Two of them are as follows:

int     getText(void* page, wchar_t*& pTextOut);
int     getTextJson(void* page, char*& jsonData);

I am using JNA and I am tring to write equivalent Java method in my interface:

int getText(Pointer pdfPage, ?? textOutput);
int getTextJson(Pointer pdfPage, ?? jsonData);

Unfortunately the following returns garbage

    Pointer outputTextPointer = outputText.getPointer();
    String outputStre = outputTextPointer.getString(0, "UTF-8");

The following returns and IndexOutOfBoundsException

    Pointer outputTextPointer = outputText.getPointer();
    String outputStre = outputTextPointer.getStringArray(0);

Can anyone recommend the correct java class to use to map the types wchar_t*& and char*& or how to get at the data correctly?

Thanks Damien

Solution

  • The following mappings work correctly for me

    int getText(Pointer page, PointerByReference pTextOut);
int getTextJson(Pointer page, PointerByReference jsonData);

    And then I use the following to get the data

    PointerByReference pTextOut = new PointerByReference();
getText(page, pTextOut);
System.out.println(pTextOut.getValue().getWideString(0));