Can i pass an int * to a native function?

Question

From Java, can I pass an int pointer to the JNI?
I want the native function to assign data to an int in the Java program.
Many thanks!

Answer 1

838478 wrote:
Many thanks to both of you for your helpful responses. I pitched my original question somewhat disingenuously in order to be precise. My actual development issue is broader:
I have C++ API that passes many data types by reference (as pointers or references) in order to modify the passed values. If I were to wrap this API to call it from from Java it sounds as though passing each parameter as an object (e.g. Integer for int would be the cleanest way to go. Does this sound correct?
One enigma: I have to call a native function with a char * argument that returns with that char * pointing to a buffer of binary data. How should I pass back that binary buffer to Java? As a String? Your problem is not specific enough.
1. You want to create data, regardless of the type, on the native heap and pass it through java to another native method. Solution: Use a long. You have a pointer to the data (again the type does NOT matter), you cast it to a long, you return that from your first method, pass it into the second, and there you cast the long back to the pointer. The pointer can point to anything you like including complex data types.
2. You want to create data, of some complex structure, on the native heap and then access that data in java. Then you MUST map it to java types, every piece of data, of every type, specific to the type. So a native int maps to a java int (if the sizes match), a char* maps to a String, etc. You MUST create in some fashion every java data item that you need. There are NO shortcuts.