QLibrary: how to download and check?

[lucky_sever]

There are some programs in C++

#include <cstdlib>
#include <iostream>
#include <windows.h>
#include "AtUsbHid.h"
 
using namespace std;
 
int main(int argc, char *argv[])
{
    HINSTANCE hLib = NULL;
    hLib =LoadLibrary(AT_USB_HID_DLL);
    if(hLib == NULL){
        cout << "boing\n";
    }
    loadFuncPointers(hLib);
 
    DYNCALL(findHidDevice)(Vid, Pid);
    DYNCALL(hidRegisterDeviceNotification)((m_hWnd));
 
    system("PAUSE");
    return EXIT_SUCCESS;
}

#include <cstdlib>
#include <iostream>
#include <windows.h>
#include "AtUsbHid.h"
 
using namespace std;
 
int main(int argc, char *argv[])
{
    HINSTANCE hLib = NULL;
    hLib =LoadLibrary(AT_USB_HID_DLL);
    if(hLib == NULL){
        cout << "boing\n";
    }
    loadFuncPointers(hLib);

    DYNCALL(findHidDevice)(Vid, Pid);
    DYNCALL(hidRegisterDeviceNotification)((m_hWnd));
 
    system("PAUSE");
    return EXIT_SUCCESS;
}

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This realization is already on the QT. What am I doing wrong?

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QLibrary>
#include <QMessageBox>
#include <cstdlib>
#include <stdio.h>
#include <conio.h>
#include <windows.h>
#include <stddef.h>
#include <windowsx.h>
 
// Include Atmel Hid Usb
#include "AtUsbHid.h"
 
#define DEFAULT_VID 0x03EB
#define DEFAULT_PID 0x2013
 
 
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
 
}
 
MainWindow::~MainWindow()
{
    delete ui;
 
    Vid = DEFAULT_VID;
    Pid = DEFAULT_PID;
}
 
 
 
void MainWindow::on_ConnectUsb_clicked()
{
            QLibrary hLib(AT_USB_HID_DLL);
            hLib.load();
 
            if (!hLib.load())
                {
                QMessageBox::warning(this, tr("Error"),
                                     tr("Not found AtUsbHid.dll"),
                                     QMessageBox::Ok);
                return;
                }
 //***********************************************************
        typedef void (*func)();
        func PF_findHidDevice = (func) hLib.resolve("findHidDevice)(Vid, Pid)");
        if (!PF_findHidDevice)
		{
            qDebug ("!!!!!!!!findHidDevice");
            return;
        }
 
 
        typedef void (*func)();
        func PF_hidRegisterDeviceNotification = (func) hLib.resolve("hidRegisterDeviceNotification");
        if (!PF_hidRegisterDeviceNotification)
            {
            qDebug ("!!!!!!!!hidRegisterDeviceNotification");
            return;
            }
//***********************************************************
}

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QLibrary>
#include <QMessageBox>
#include <cstdlib>
#include <stdio.h>
#include <conio.h>
#include <windows.h>
#include <stddef.h>
#include <windowsx.h>

// Include Atmel Hid Usb
#include "AtUsbHid.h"

#define DEFAULT_VID 0x03EB
#define DEFAULT_PID 0x2013



MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

}

MainWindow::~MainWindow()
{
    delete ui;

    Vid = DEFAULT_VID;
    Pid = DEFAULT_PID;
}



void MainWindow::on_ConnectUsb_clicked()
{
            QLibrary hLib(AT_USB_HID_DLL);
            hLib.load();

            if (!hLib.load())
                {
                QMessageBox::warning(this, tr("Error"),
                                     tr("Not found AtUsbHid.dll"),
                                     QMessageBox::Ok);
                return;
                }
 //***********************************************************
        typedef void (*func)();
        func PF_findHidDevice = (func) hLib.resolve("findHidDevice)(Vid, Pid)");
        if (!PF_findHidDevice)
		{
            qDebug ("!!!!!!!!findHidDevice");
            return;
        }


        typedef void (*func)();
        func PF_hidRegisterDeviceNotification = (func) hLib.resolve("hidRegisterDeviceNotification");
        if (!PF_hidRegisterDeviceNotification)
            {
            qDebug ("!!!!!!!!hidRegisterDeviceNotification");
            return;
            }
//***********************************************************
}

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[d_stranz]

Have you read the QLibrary documentation? From the docs:

The symbol must be exported as a C function from the library for resolve() to work. This means that the function must be wrapped in an extern "C" block if the library is compiled with a C++ compiler. On Windows, this also requires the use of a dllexport macro; see resolve() for the details of how this is done.

Do you know anything about your library? Is it a C or a C++ library?

What do you see when you look at it using the Visual Studio "dumpbin" tool? (Start a Visual Studio command window, cd to your dll folder, and type "dumpbin /EXPORTS AtUsbHid.dll"). This will show you the names of all of the exported classes and methods in the DLL. If you see things like this (from the Qwt 6.0 DLL):

?pinPoint@QwtSymbol@@QBE?AVQPointF@@XZ

then this means your library is a C++ library and has C++ mangled names. If you see something like this (from pgort90.dll, in the Visual Studio distribution):

IrtAutoSweepA

then this means it is a C library, or that the symbols in it were exported using the extern "C" declaration described in the docs.

[lucky_sever]

library C++

[d_stranz]

OK, then try using resolve() with one of the mangled names you see in that dump, and see if that succeeds.

[lucky_sever]

So I try to resolve (), the above code. But something does not work.

[d_stranz]

Is there some reason why you hve to load this DLL at run time? Don't you have an import library (.lib) that you can link to, so the DLL can be loaded automatically when the program runs? You have the header file (.h), so why not use the .lib at link time?

And did you look at the value return by the QLibrary::errorString() method to see what it says when the resolve() call fails?

[lucky_sever]

dumpbin.exe /exports

Microsoft (R) COFF/PE Dumper Version 10.00.30319.01
Copyright (C) Microsoft Corporation.  All rights reserved.
 
 
Dump of file AtUsbHid.dll
 
File Type: DLL
 
  Section contains the following exports for AtUsbHid.dll
 
    00000000 characteristics
    479752C1 time date stamp Wed Jan 23 16:44:17 2008
        0.00 version
           1 ordinal base
          21 number of functions
          21 number of names
 
    ordinal hint RVA      name
 
          2    0 0000198D closeDevice
          3    1 000011CF findHidDevice
          4    2 00002103 getFeatureReportLength
          5    3 000020F3 getInputReportLength
          6    4 000020E3 getOutputReportLength
          7    5 00001EB0 getch
          8    6 00001FA0 hidRegisterDeviceNotification
          9    7 00001F8F hidUnregisterDeviceNotification
         10    8 00001FFD isMyDeviceNotification
         11    9 00001000 openDevice
         12    A 00001E62 putch
         13    B 00001CE5 readContinuous
         14    C 00001D1F readData
         15    D 00001C13 readStandard
         16    E 0000204D setFeature
         17    F 00001AE7 setReportContinuous
         18   10 00001F63 setTxPeriod
          1   11 00001DED updateFeatureBytes
         19   12 00001D2F writeContinuous
         20   13 00001DDD writeData
         21   14 00001B1D writeStandard
 
  Summary
 
        5000 .data
        2000 .rdata
        1000 .reloc
        1000 .rsrc
        8000 .text

Microsoft (R) COFF/PE Dumper Version 10.00.30319.01
Copyright (C) Microsoft Corporation.  All rights reserved.


Dump of file AtUsbHid.dll

File Type: DLL

  Section contains the following exports for AtUsbHid.dll

    00000000 characteristics
    479752C1 time date stamp Wed Jan 23 16:44:17 2008
        0.00 version
           1 ordinal base
          21 number of functions
          21 number of names

    ordinal hint RVA      name

          2    0 0000198D closeDevice
          3    1 000011CF findHidDevice
          4    2 00002103 getFeatureReportLength
          5    3 000020F3 getInputReportLength
          6    4 000020E3 getOutputReportLength
          7    5 00001EB0 getch
          8    6 00001FA0 hidRegisterDeviceNotification
          9    7 00001F8F hidUnregisterDeviceNotification
         10    8 00001FFD isMyDeviceNotification
         11    9 00001000 openDevice
         12    A 00001E62 putch
         13    B 00001CE5 readContinuous
         14    C 00001D1F readData
         15    D 00001C13 readStandard
         16    E 0000204D setFeature
         17    F 00001AE7 setReportContinuous
         18   10 00001F63 setTxPeriod
          1   11 00001DED updateFeatureBytes
         19   12 00001D2F writeContinuous
         20   13 00001DDD writeData
         21   14 00001B1D writeStandard

  Summary

        5000 .data
        2000 .rdata
        1000 .reloc
        1000 .rsrc
        8000 .text

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[d_stranz]

This is a C library, not a C++ library.

Create a Qt Console Application, and insert this code in main(). What do you see when this code runs?

#include <QtCore/QCoreApplication>
#include <QLibrary>
#include <iostream>
 
int main(int argc, char *argv[])
{
	QCoreApplication a(argc, argv);
 
 
	QLibrary	qLib( "AtUsbHid.dll" );
	if ( qLib.load() )
	{
		void *	func = qLib.resolve( "openDevice" );
		if ( 0 == func )
			std::cout << qLib.errorString().toStdString() << std::endl;
		else
			std::cout << "No errors" << std::endl;
	}
	else
		std::cout << qLib.errorString().toStdString() << std::endl;
	return a.exec();
}

#include <QtCore/QCoreApplication>
#include <QLibrary>
#include <iostream>

int main(int argc, char *argv[])
{
	QCoreApplication a(argc, argv);


	QLibrary	qLib( "AtUsbHid.dll" );
	if ( qLib.load() )
	{
		void *	func = qLib.resolve( "openDevice" );
		if ( 0 == func )
			std::cout << qLib.errorString().toStdString() << std::endl;
		else
			std::cout << "No errors" << std::endl;
	}
	else
		std::cout << qLib.errorString().toStdString() << std::endl;
	return a.exec();
}

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