Call VS6 C DLL function from java code

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i make a simple c function in Visual studio 6 this is the code

C++

#include "stdafx.h"
BOOL APIENTRY DllMain( HANDLE hModule,DWORD  ul_reason_for_call,LPVOID lpReserved)


{
    return TRUE;
}

extern "C" __declspec(dllexport) char __stdcall GetCompanyCode()
{
    return 1;
}

i need to call the function GetCompanyCode from java so i used JNA at first i create Interface in java

Java

package javaapplication4;
import com.sun.jna.Library;
/**
 *
 * @author amir
 */
public interface CompanyCode extends Library
{
    public  byte GetCompanyCode();
}

then load the dll

Java

import java.io.FileNotFoundException;
import java.io.IOException;
import com.sun.jna.Native;
import java.security.NoSuchAlgorithmException;
import java.sql.SQLException;

/**
 *
 * @author amir
 */
public class JavaApplication4 
{
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws  IOException, FileNotFoundException, NoSuchAlgorithmException 
    {
        System.setProperty("jna.library.path", "C:/");
        CompanyCode Company= (CompanyCode)Native.loadLibrary("CompanyCode", CompanyCode.class);
        byte x=Company.GetCompanyCode();
        System.out.println(x);
    }
}

i got the error

Quote:
Exception in thread "main" java.lang.UnsatisfiedLinkError: Error looking up function 'GetCompanyCode': The specified procedure could not be found.

at com.sun.jna.Function.(Function.java:179) at com.sun.jna.NativeLibrary.getFunction(NativeLibrary.java:347) at com.sun.jna.NativeLibrary.getFunction(NativeLibrary.java:327) at com.sun.jna.Library$Handler.invoke(Library.java:203) at com.sun.proxy.$Proxy0.GetCompanyCode(Unknown Source) at javaapplication4.JavaApplication4.main(JavaApplication4.java:28) C:\Users\amir\AppData\Local\NetBeans\Cache\8.2\executor-snippets\run.xml:53: Java returned: 1 BUILD FAILED (total time: 0 seconds)

what should i do?

What I have tried:

now i don't know what else i should do, i googled lot but what i found i already did

Posted 23-Apr-17 23:19pm

amir tarek

Updated 23-Apr-17 23:41pm

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KarstenK · Accepted Answer · 2017-04-23T23:41:00

Solution 1

You must carefully read and understand the error message. Here is "Error looking up function 'GetCompanyCode': The specified procedure could not be found."

So the linker says that dll is found but the function not. Check with the good olddepedency walker that the function name is properly exported. My guess is that the __stdcall makes some changes in the so called decorated name.

And I would export an int as result, because it is native data type.

Posted 23-Apr-17 23:41pm

KarstenK

Comments

amir tarek 24-Apr-17 5:47am

i tried dependency walker and the function name is _GetCompanyCode@0 so how i convert the name to GetCompanyCode?

amir tarek 24-Apr-17 6:00am

i solved it i user StdCallFunctionMapper to change the name