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JNI - mapping integer pointers in vc++ through JNI

Posted on 2001-07-26
Last Modified: 2013-11-23
Hi! Anyone,
I have a native function defined in VC++ which is returning int*.  Actually I would like to map this int * with JNI.  Do anyone throw some light on this.  

Thanks in advance.
Question by:Jeganathan

Expert Comment

ID: 6322669
If you mean you simply want to store it, you can stuff it into int or long member data using JNI member access methods.

Otherwise you'll need to clarify what you mean by mapping the integer pointer.


Author Comment

ID: 6326141
My VC++ native function looks something like this

JNIEXPORT int* JNICALL readSrl(JNIEnv *env, jobject obj)
  int* srl = new int[8];

  byte [] b = {1,2,3,4,5,6,7,8};

  for(int i=0; i<8; ++i)
    srl[i] = b[i];

 return srl;

Can anyone suggest the method signature that should be declared in Java using this native function.  


Accepted Solution

stimpyjcat earned 50 total points
ID: 6326438
So it's not that you want to store a pointer to an integer, you want to store an array of integers.

To see the proper signature for returning an array of integers, do the following:

1) compile a simple java function which returns the type you're interested in (int[]), e.g.

public class Serial {
int[] readSrl() {
     return new int[] { 1,2,3,4,5,6,7,8 };

2) run javap to get the signature

javap -s Serial

It might be preferable to convert the serial to a string, since it's far easier to construct a jstring from a character array than to construct an array of jints and populate it.  If you're only interested in the unique pattern of bits, that might be preferable.  If you're interested in the individual integers, though, you should construct a java array of integers instead.

There are array copy functions in JNI which can make this a little easier; see the JNI tutorial at java.sun.com.

Expert Comment

ID: 9061947
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Expert Comment

ID: 9208320
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