0

I am new to using JNA.In all what i want to do is use the vb DLL file in java & call the functions from java. I created a simple java code for this.

import com.sun.jna.Library; import com.sun.jna.Native; import com.sun.jna.Platform; public class Main { public interface test extends Library { void fn_Today(int a,int b); } public static void main(String[] args) { test INSTANCE = (test) Native.loadLibrary( (Platform.isWindows() ? "test" : "test"), test.class); int a = 1; int b=2; INSTANCE .fn_Today(a,b); } }

When i run this java program i am getting following error-

Exception in thread "main" java.lang.UnsatisfiedLinkError: Error looking up function 'fn_Today': The specified procedure could not be found. at com.sun.jna.Function.<init>(Function.java:179) at com.sun.jna.NativeLibrary.getFunction(NativeLibrary.java:344) at com.sun.jna.NativeLibrary.getFunction(NativeLibrary.java:324) at com.sun.jna.Library$Handler.invoke(Library.java:203) at com.sun.proxy.$Proxy0.fn_Today(Unknown Source) at mwrobel.jna.Main.main(Main.java:27) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)

Dll code is as

Public Function fn_Today(ival As Integer, ival2 As Integer) Dim ret As Integer ret = ival + ival2 End Function

How can i solved this issue?

i got the following output from dependency walker.

Warning: At least one delay-load dependency module was not found. Warning: At least one module has an unresolved import due to a missing export function in a delay-load dependent module.
Improve this question
7
  • This might be applicable: stackoverflow.com/questions/30565496/… Commented Jun 2, 2015 at 7:30
  • And this one: stackoverflow.com/questions/22695829/… Commented Jun 2, 2015 at 7:32
  • VB DLLs use the stdcall calling convention, so at the very least you need to implement StdCallLibrary instead of Library. Commented Jun 2, 2015 at 13:08
  • You likely also need to use a StdCallFunctionMapper to decorate function names according to stdcall conventions. Commented Jun 2, 2015 at 13:09
  • BTW, running Dependency Walker on your DLL will show you the actual labels exported for your functions. See also the JNA FAQ. Commented Jun 2, 2015 at 15:45

1 Answer 1

Reset to default
1

If your VB DLL is a C-compatible shared library (if you run Dependency Walker on it you'll see labels of the form XXX@NNN), then the following should work.

import com.sun.jna.win32.StdCallFunctionMapper; import com.sun.jna.win32.StdCallLibrary; public class Main { public interface TestLibrary extends StdCallLibrary { void fn_Today(int a,int b); } public static void main(String[] args) { Map options = new HashMap() { { put(Library.OPTION_FUNCTION_MAPPER, new StdCallFunctionMapper()) } }; TestLibrary INSTANCE = (TestLibrary) Native.loadLibrary("test", TestLibrary.class, options); // ... } }
Improve this answer
Sign up to request clarification or add additional context in comments.

5 Comments

i am still getting this error. I think problem is in dll .How do i know VB DLL is a C-compatible shared library or not? @technomage
Include the relevant output from DependencyWalker in your question. You should also add an update to your question which reflects the changes you've made thus far.
i did add an update in my question .See and give me response @technomage
Did you update your code to match the example in the answer? What did symbols does dependency walker show are in your DLL?
i got Warning: At least one delay-load dependency module was not found. Warning: At least one module has an unresolved import due to a missing export function in a delay-load dependent module.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.