1  // Purpose.  Java calling C
 2  //           (Java passes int in, C returns int)
   
   
 3  ////////////////////////////// JNIdemos.java \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
   
 4  class JNIdemos {
 5     public native static int toDouble( int in );
 6     static {
 7        System.loadLibrary( "JNIdemos" );
 8     }
 9     public static void main( String[] args ) {
10        System.out.println( "JNIdemos.java: entry" );
11        System.out.println( "   double is "
12                            + toDouble( Integer.parseInt(args[0]) ) );
13        System.out.println( "JNIdemos.java: exit" );
14     }
15  }
   
   
16  /////////////////////////////// JNIdemos.h \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
   
17  /* DO NOT EDIT THIS FILE - it is machine generated **
18  #include <jni.h>
19  /* Header for class JNIdemos **
   
20  #ifndef _Included_JNIdemos
21  #define _Included_JNIdemos
22  #ifdef __cplusplus
23  extern "C" {
24  #endif
25  /*
26   * Class:     JNIdemos
27   * Method:    toDouble
28   * Signature: (I)I
29   **
30  JNIEXPORT jint JNICALL Java_JNIdemos_toDouble( JNIEnv*, jclass, jint );
31  #ifdef __cplusplus
32  }
33  #endif
34  #endif
   
   
35  ////////////////////////////// JNIdemos.cpp \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
   
36  #include <iostream.h>
37  #include "JNIdemos.h"
   
38  extern "C" {
39  JNIEXPORT jint JNICALL Java_JNIdemos_toDouble( JNIEnv*, jclass, jint in ) {
40     cout << "JNIdemos.cpp:  in is " << in << ", out is " << in * 2 << endl;
41     return in * 2;
42  }
43  }
   
   
44  // C:> java JNIdemos 42
45  // JNIdemos.java: entry
46  // JNIdemos.cpp:  in is 42, out is 84
47  //    double is 84
48  // JNIdemos.java: exit