GCJ: Is it possible to call C++ from Java using GCJ CNI?

[Andrew Haley]

Gareth Buxton wrote:

> I have been trying to find out how to call C++ code from Java using
> CNI. Is this at all possible?
> 
> I found this page in the documentation which suggests a possible way:
> 
> http://gcc.gnu.org/onlinedocs/gcj/Interfaces.html#Interfaces
> 
> But I have been unable to make anything  work using this. Are there
> any code examples?

All of libgcj.  Here's a simple example:

java/lang/VMFloat.java:

package java.lang;


final class VMFloat
{
  ...  

  static native int floatToIntBits(float value);



natVMFloat.cc:

jint 
java::lang::VMFloat::floatToRawIntBits(jfloat value)
{
  union u u;
  u.d = value;  
  return u.l;
}

Andrew.