Question

I’m developing a java application that uses some jni calls.

I have on C code the following variable:

GLuint *vboIds;

I want to pass this variable from Java to C, but I don’t know how to declare it in Java.

GLuint is equivalent an unsigned int.

So, I think this is the equivalent declaration in Java:

int[] vboIds;

What do you think?

Thanks

Answer 1

You don’t say explicitly whether it is meant to be a pointer to a single value or an array, but I’d guess it’s probably an array from the naming and what you are thinking of doing with the mapping (there should also be a parameter somewhere that specifies the length of the array; those both map to the same argument on the Java side as Java’s arrays know their own lengths). You’re probably right to use an int as that’s generally the same size as a C int – not that that’s a guarantee, not at all, but hardly any machine architectures are different from that these days – but you’ll need to watch out for the fact that Java’s numeric types are all signed. That’s mostly not a problem provided you’re a bit careful with arithmetic (other than addition, subtraction and left-shift, which work obviously) and comparisons.