C++ Function with pointer as parameter and Handle it with swig interface

Question

I have created swig interface file to create JNI for my C++ Files. but some of my C++ Files include functions which accept pointer as argument like (void*) , C++ BOOL and Swig converts it into type like SWIGTYPE_p_int32_t how to pass such kind of data type from java ?

for example one of the function's actual prototype is like below in C++

DLL_API void DLL_CALLCONV FreeImage_Initialise(BOOL load_local_plugins_only FI_DEFAULT(FALSE));

which is converted in Java file with swig

public static void FreeImage_Initialise(SWIGTYPE_p_int32_t load_local_plugins_only)

how to pass such value from java ?

I have many classes which include such kind of arguments in function. is there any way so that I can apply solution to bulk files for handle datatype as simple as possible.

I have read one way to do that is create helper function but I cannot go for it because i have many c++ classes and for each and every function creating helper function for returning pointer is not way to go.

Please suggest any other way if possible.

Answer 1

Solved myself. Swig was not be able to recognize all the typedef in header files and hence it was producing that kind of Types in wrapper. I need to redefine them in Interface file.

Answer 2

About booleans, I would recommend using boolinstead of BOOL because JNI directly provides a type signature for it: Z (you can check signatures at: JNI Types and Data Structures)

About pointers, if are pointer to basic types, this is declared by adding [in front of corresponding signature, this is: int* --> [I. If it's a pointer to a own class, swig will create a fully qualified class.

Hope this helps.

Answer 3

This is because of the weird declaration of BOOL type.

In this particular case, you can pass an int there from Java side. Either 0 or 1 will do the right job.

Or you can change BOOL to bool in your native code by creating a small wrapper for this library.

Answer 4

SWIG doesn't know about windows types. Add %include <windows.i> to the interface definition.