Should i necessarily first have a .h and then convert it to a .dll?

Question

hi.
i want to use windows 98 APIs.
but i recieve a linker error. i've see many
JNI example that convert a header file to a .dll
but is windows we have .DLLs not header!?
should i necessarily first have a .h and then
convert it to a .dll?
it's my code:
public class JNItest
long returnValue;
static
System.loadLibrary("user32");
public native long EmptyClipboard();
public void free()
returnValue = EmptyClipboard();
public static void main(String args[])
new JNItest().free();
I SET THE PATH OF SYSTEM DIRECTORY OF WINDOWS FOR LINKER TO FIND
USER32.DLL BUT I RECIEVE THIS ERROR:
Exception in thread "main" java.lang.UnsatisfiedLinkError: EmptyClipboard
at JNItest.EmptyClipboard(Native Method)
at JNItest.play(JNItest.java:14)
at JNItest.main(JNItest.java:18)
please help.
thanks a world.

Answer 1

You can't call EmptyClipboard directly from your Java code.
You need to run javah against that source file. It will generate a C++ header file with the definition of the native method you declare in your Java file. You create a C++ DLL that includes that header file and implement that stub function in C++. It will simply call the Win32 EmptyClipboard function.
Then, you add a line in your Java source to loadLibrary the new DLL after User32, and it should work. See the JNI tutorial for details.
Tim