lcrogers
asked on
DLL Blues, Where did I go Wrong???
I am trying to create a dll file. I have about 40 functions that I want to store in a DLL file and make calls sto them from other msv 7.1C++ programs. So looked at some examples and decided to try one first before going to a large one. I tried 3 exsamples and always got a linking error when I tried to call one of the functions in the dll file i created. Pls hlelp me find out where I am going wrong. Here is a sample of the last code that I wrote. The dll file complies fine but to program to make a call to it does not. I used the mfc wizard to create the wizard and added the functions. I commented where I added my code lines. Could you please Debus this one or send me a sample of one that works so I can use it as a template??? I want to pass strings and numerical values to the calling applications. Thanks in advance for your assistance. I will be passing string and numbers in my functions.
DLL Program
the H File
// The following ifdef block is the standard way of creating macros which make exporting
// from a DLL simpler. All files within this DLL are compiled with the TESTDLL_EXPORTS
// symbol defined on the command line. this symbol should not be defined on any project
// that uses this DLL. This way any other project whose source files include this file see
// TESTDLL_API functions as being imported from a DLL, whereas this DLL sees symbols
// defined with this macro as being exported.
#ifdef TESTDLL_EXPORTS
#define TESTDLL_API __declspec(dllexport)
#else
#define TESTDLL_API __declspec(dllimport)
#endif
// This class is exported from the TESTDLL.dll
class TESTDLL_API CTESTDLL {
public:
CTESTDLL(void);
// TODO: add your methods here.
};
extern TESTDLL_API int nTESTDLL;
TESTDLL_API int fnTESTDLL(void);
the CPP file
// TESTDLL.cpp : Defines the entry point for the DLL application.
//
#include "stdafx.h"
#define TESTDLL_EXPORTS // I added this line *******************
#include "TESTDLL.h"
BOOL APIENTRY DllMain( HANDLE hModule,
DWORD ul_reason_for_call,
LPVOID lpReserved
)
{
switch (ul_reason_for_call)
{
case DLL_PROCESS_ATTACH:
case DLL_THREAD_ATTACH:
case DLL_THREAD_DETACH:
case DLL_PROCESS_DETACH:
break;
}
return TRUE;
}
// This is an example of an exported variable
TESTDLL_API int nTESTDLL=0;
// This is an example of an exported function.
TESTDLL_API int fnTESTDLL(void)
{
return 42;
}
// This is the constructor of a class that has been exported.
// see TESTDLL.h for the class definition
CString CTESTDLL::CTESTDLL()
{
return "Test message.";
}
////////////////////////// ///////// The program that calls the Dll
the H Files
// TestCall.h : main header file for the PROJECT_NAME application
//
#pragma once
#ifndef __AFXWIN_H__
#error include 'stdafx.h' before including this file for PCH
#endif
#include "resource.h" // main symbols
// CTestCallApp:
// See TestCall.cpp for the implementation of this class
//
class CTestCallApp : public CWinApp
{
public:
CTestCallApp();
// Overrides
public:
virtual BOOL InitInstance();
// Implementation
DECLARE_MESSAGE_MAP()
};
extern CTestCallApp theApp;
// TestCallDlg.h : header file
//
#pragma once
// CTestCallDlg dialog
class CTestCallDlg : public CDialog
{
// Construction
public:
CTestCallDlg(CWnd* pParent = NULL); // standard constructor
// Dialog Data
enum { IDD = IDD_TESTCALL_DIALOG };
protected:
virtual void DoDataExchange(CDataExchan ge* pDX); // DDX/DDV support
// Implementation
protected:
HICON m_hIcon;
// Generated message map functions
virtual BOOL OnInitDialog();
afx_msg void OnSysCommand(UINT nID, LPARAM lParam);
afx_msg void OnPaint();
afx_msg HCURSOR OnQueryDragIcon();
DECLARE_MESSAGE_MAP()
};
The CPP Files
// TestCall.cpp : Defines the class behaviors for the application.
//
#include "stdafx.h"
#include "TestCall.h"
#include "TestCallDlg.h"
#ifdef _DEBUG
#define new DEBUG_NEW
#endif
// CTestCallApp
BEGIN_MESSAGE_MAP(CTestCal lApp, CWinApp)
ON_COMMAND(ID_HELP, CWinApp::OnHelp)
END_MESSAGE_MAP()
// CTestCallApp construction
CTestCallApp::CTestCallApp ()
{
// TODO: add construction code here,
// Place all significant initialization in InitInstance
}
// The one and only CTestCallApp object
CTestCallApp theApp;
// CTestCallApp initialization
BOOL CTestCallApp::InitInstance ()
{
// InitCommonControls() is required on Windows XP if an application
// manifest specifies use of ComCtl32.dll version 6 or later to enable
// visual styles. Otherwise, any window creation will fail.
InitCommonControls();
CWinApp::InitInstance();
AfxEnableControlContainer( );
// Standard initialization
// If you are not using these features and wish to reduce the size
// of your final executable, you should remove from the following
// the specific initialization routines you do not need
// Change the registry key under which our settings are stored
// TODO: You should modify this string to be something appropriate
// such as the name of your company or organization
SetRegistryKey(_T("Local AppWizard-Generated Applications"));
CTestCallDlg dlg;
m_pMainWnd = &dlg;
INT_PTR nResponse = dlg.DoModal();
if (nResponse == IDOK)
{
// TODO: Place code here to handle when the dialog is
// dismissed with OK
}
else if (nResponse == IDCANCEL)
{
// TODO: Place code here to handle when the dialog is
// dismissed with Cancel
}
// Since the dialog has been closed, return FALSE so that we exit the
// application, rather than start the application's message pump.
return FALSE;
}
// TestCallDlg.cpp : implementation file
//
#include "stdafx.h"
#include "TestCall.h"
#include "TestCallDlg.h"
#include "TESTDLL.h" // I added this line
#ifdef _DEBUG
#define new DEBUG_NEW
#endif
// CAboutDlg dialog used for App About
class CAboutDlg : public CDialog
{
public:
CAboutDlg();
// Dialog Data
enum { IDD = IDD_ABOUTBOX };
protected:
virtual void DoDataExchange(CDataExchan ge* pDX); // DDX/DDV support
// Implementation
protected:
DECLARE_MESSAGE_MAP()
};
CAboutDlg::CAboutDlg() : CDialog(CAboutDlg::IDD)
{
}
void CAboutDlg::DoDataExchange( CDataExcha nge* pDX)
{
CDialog::DoDataExchange(pD X);
}
BEGIN_MESSAGE_MAP(CAboutDl g, CDialog)
END_MESSAGE_MAP()
// CTestCallDlg dialog
CTestCallDlg::CTestCallDlg (CWnd* pParent /*=NULL*/)
: CDialog(CTestCallDlg::IDD, pParent)
{
m_hIcon = AfxGetApp()->LoadIcon(IDR_ MAINFRAME) ;
}
void CTestCallDlg::DoDataExchan ge(CDataEx change* pDX)
{
CDialog::DoDataExchange(pD X);
}
BEGIN_MESSAGE_MAP(CTestCal lDlg, CDialog)
ON_WM_SYSCOMMAND()
ON_WM_PAINT()
ON_WM_QUERYDRAGICON()
//}}AFX_MSG_MAP
END_MESSAGE_MAP()
// CTestCallDlg message handlers
BOOL CTestCallDlg::OnInitDialog ()
{
CDialog::OnInitDialog();
// Add "About..." menu item to system menu.
// IDM_ABOUTBOX must be in the system command range.
ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
ASSERT(IDM_ABOUTBOX < 0xF000);
CMenu* pSysMenu = GetSystemMenu(FALSE);
if (pSysMenu != NULL)
{
CString strAboutMenu;
strAboutMenu.LoadString(ID S_ABOUTBOX );
if (!strAboutMenu.IsEmpty())
{
pSysMenu->AppendMenu(MF_SE PARATOR);
pSysMenu->AppendMenu(MF_ST RING, IDM_ABOUTBOX, strAboutMenu);
}
}
// Set the icon for this dialog. The framework does this automatically
// when the application's main window is not a dialog
SetIcon(m_hIcon, TRUE); // Set big icon
SetIcon(m_hIcon, FALSE); // Set small icon
// TODO: Add extra initialization here
// Code to test TESTDLL.dll Program
int n = fnTESTDLL(); /// I added this line and Here is where I am getting the linking errors.*****************
// Code to test the CTestdll class
CTESTDLL test; /// I added this line and Here is where I am getting the linking errors. *****************
return TRUE; // return TRUE unless you set the focus to a control
}
void CTestCallDlg::OnSysCommand (UINT nID, LPARAM lParam)
{
if ((nID & 0xFFF0) == IDM_ABOUTBOX)
{
CAboutDlg dlgAbout;
dlgAbout.DoModal();
}
else
{
CDialog::OnSysCommand(nID, lParam);
}
}
// If you add a minimize button to your dialog, you will need the code below
// to draw the icon. For MFC applications using the document/view model,
// this is automatically done for you by the framework.
void CTestCallDlg::OnPaint()
{
if (IsIconic())
{
CPaintDC dc(this); // device context for painting
SendMessage(WM_ICONERASEBK GND, reinterpret_cast<WPARAM>(d c.GetSafeH dc()), 0);
// Center icon in client rectangle
int cxIcon = GetSystemMetrics(SM_CXICON );
int cyIcon = GetSystemMetrics(SM_CYICON );
CRect rect;
GetClientRect(&rect);
int x = (rect.Width() - cxIcon + 1) / 2;
int y = (rect.Height() - cyIcon + 1) / 2;
// Draw the icon
dc.DrawIcon(x, y, m_hIcon);
}
else
{
CDialog::OnPaint();
}
}
// The system calls this function to obtain the cursor to display while the user drags
// the minimized window.
HCURSOR CTestCallDlg::OnQueryDragI con()
{
return static_cast<HCURSOR>(m_hIc on);
}
DLL Program
the H File
// The following ifdef block is the standard way of creating macros which make exporting
// from a DLL simpler. All files within this DLL are compiled with the TESTDLL_EXPORTS
// symbol defined on the command line. this symbol should not be defined on any project
// that uses this DLL. This way any other project whose source files include this file see
// TESTDLL_API functions as being imported from a DLL, whereas this DLL sees symbols
// defined with this macro as being exported.
#ifdef TESTDLL_EXPORTS
#define TESTDLL_API __declspec(dllexport)
#else
#define TESTDLL_API __declspec(dllimport)
#endif
// This class is exported from the TESTDLL.dll
class TESTDLL_API CTESTDLL {
public:
CTESTDLL(void);
// TODO: add your methods here.
};
extern TESTDLL_API int nTESTDLL;
TESTDLL_API int fnTESTDLL(void);
the CPP file
// TESTDLL.cpp : Defines the entry point for the DLL application.
//
#include "stdafx.h"
#define TESTDLL_EXPORTS // I added this line *******************
#include "TESTDLL.h"
BOOL APIENTRY DllMain( HANDLE hModule,
DWORD ul_reason_for_call,
LPVOID lpReserved
)
{
switch (ul_reason_for_call)
{
case DLL_PROCESS_ATTACH:
case DLL_THREAD_ATTACH:
case DLL_THREAD_DETACH:
case DLL_PROCESS_DETACH:
break;
}
return TRUE;
}
// This is an example of an exported variable
TESTDLL_API int nTESTDLL=0;
// This is an example of an exported function.
TESTDLL_API int fnTESTDLL(void)
{
return 42;
}
// This is the constructor of a class that has been exported.
// see TESTDLL.h for the class definition
CString CTESTDLL::CTESTDLL()
{
return "Test message.";
}
//////////////////////////
the H Files
// TestCall.h : main header file for the PROJECT_NAME application
//
#pragma once
#ifndef __AFXWIN_H__
#error include 'stdafx.h' before including this file for PCH
#endif
#include "resource.h" // main symbols
// CTestCallApp:
// See TestCall.cpp for the implementation of this class
//
class CTestCallApp : public CWinApp
{
public:
CTestCallApp();
// Overrides
public:
virtual BOOL InitInstance();
// Implementation
DECLARE_MESSAGE_MAP()
};
extern CTestCallApp theApp;
// TestCallDlg.h : header file
//
#pragma once
// CTestCallDlg dialog
class CTestCallDlg : public CDialog
{
// Construction
public:
CTestCallDlg(CWnd* pParent = NULL); // standard constructor
// Dialog Data
enum { IDD = IDD_TESTCALL_DIALOG };
protected:
virtual void DoDataExchange(CDataExchan
// Implementation
protected:
HICON m_hIcon;
// Generated message map functions
virtual BOOL OnInitDialog();
afx_msg void OnSysCommand(UINT nID, LPARAM lParam);
afx_msg void OnPaint();
afx_msg HCURSOR OnQueryDragIcon();
DECLARE_MESSAGE_MAP()
};
The CPP Files
// TestCall.cpp : Defines the class behaviors for the application.
//
#include "stdafx.h"
#include "TestCall.h"
#include "TestCallDlg.h"
#ifdef _DEBUG
#define new DEBUG_NEW
#endif
// CTestCallApp
BEGIN_MESSAGE_MAP(CTestCal
ON_COMMAND(ID_HELP, CWinApp::OnHelp)
END_MESSAGE_MAP()
// CTestCallApp construction
CTestCallApp::CTestCallApp
{
// TODO: add construction code here,
// Place all significant initialization in InitInstance
}
// The one and only CTestCallApp object
CTestCallApp theApp;
// CTestCallApp initialization
BOOL CTestCallApp::InitInstance
{
// InitCommonControls() is required on Windows XP if an application
// manifest specifies use of ComCtl32.dll version 6 or later to enable
// visual styles. Otherwise, any window creation will fail.
InitCommonControls();
CWinApp::InitInstance();
AfxEnableControlContainer(
// Standard initialization
// If you are not using these features and wish to reduce the size
// of your final executable, you should remove from the following
// the specific initialization routines you do not need
// Change the registry key under which our settings are stored
// TODO: You should modify this string to be something appropriate
// such as the name of your company or organization
SetRegistryKey(_T("Local AppWizard-Generated Applications"));
CTestCallDlg dlg;
m_pMainWnd = &dlg;
INT_PTR nResponse = dlg.DoModal();
if (nResponse == IDOK)
{
// TODO: Place code here to handle when the dialog is
// dismissed with OK
}
else if (nResponse == IDCANCEL)
{
// TODO: Place code here to handle when the dialog is
// dismissed with Cancel
}
// Since the dialog has been closed, return FALSE so that we exit the
// application, rather than start the application's message pump.
return FALSE;
}
// TestCallDlg.cpp : implementation file
//
#include "stdafx.h"
#include "TestCall.h"
#include "TestCallDlg.h"
#include "TESTDLL.h" // I added this line
#ifdef _DEBUG
#define new DEBUG_NEW
#endif
// CAboutDlg dialog used for App About
class CAboutDlg : public CDialog
{
public:
CAboutDlg();
// Dialog Data
enum { IDD = IDD_ABOUTBOX };
protected:
virtual void DoDataExchange(CDataExchan
// Implementation
protected:
DECLARE_MESSAGE_MAP()
};
CAboutDlg::CAboutDlg() : CDialog(CAboutDlg::IDD)
{
}
void CAboutDlg::DoDataExchange(
{
CDialog::DoDataExchange(pD
}
BEGIN_MESSAGE_MAP(CAboutDl
END_MESSAGE_MAP()
// CTestCallDlg dialog
CTestCallDlg::CTestCallDlg
: CDialog(CTestCallDlg::IDD,
{
m_hIcon = AfxGetApp()->LoadIcon(IDR_
}
void CTestCallDlg::DoDataExchan
{
CDialog::DoDataExchange(pD
}
BEGIN_MESSAGE_MAP(CTestCal
ON_WM_SYSCOMMAND()
ON_WM_PAINT()
ON_WM_QUERYDRAGICON()
//}}AFX_MSG_MAP
END_MESSAGE_MAP()
// CTestCallDlg message handlers
BOOL CTestCallDlg::OnInitDialog
{
CDialog::OnInitDialog();
// Add "About..." menu item to system menu.
// IDM_ABOUTBOX must be in the system command range.
ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
ASSERT(IDM_ABOUTBOX < 0xF000);
CMenu* pSysMenu = GetSystemMenu(FALSE);
if (pSysMenu != NULL)
{
CString strAboutMenu;
strAboutMenu.LoadString(ID
if (!strAboutMenu.IsEmpty())
{
pSysMenu->AppendMenu(MF_SE
pSysMenu->AppendMenu(MF_ST
}
}
// Set the icon for this dialog. The framework does this automatically
// when the application's main window is not a dialog
SetIcon(m_hIcon, TRUE); // Set big icon
SetIcon(m_hIcon, FALSE); // Set small icon
// TODO: Add extra initialization here
// Code to test TESTDLL.dll Program
int n = fnTESTDLL(); /// I added this line and Here is where I am getting the linking errors.*****************
// Code to test the CTestdll class
CTESTDLL test; /// I added this line and Here is where I am getting the linking errors. *****************
return TRUE; // return TRUE unless you set the focus to a control
}
void CTestCallDlg::OnSysCommand
{
if ((nID & 0xFFF0) == IDM_ABOUTBOX)
{
CAboutDlg dlgAbout;
dlgAbout.DoModal();
}
else
{
CDialog::OnSysCommand(nID,
}
}
// If you add a minimize button to your dialog, you will need the code below
// to draw the icon. For MFC applications using the document/view model,
// this is automatically done for you by the framework.
void CTestCallDlg::OnPaint()
{
if (IsIconic())
{
CPaintDC dc(this); // device context for painting
SendMessage(WM_ICONERASEBK
// Center icon in client rectangle
int cxIcon = GetSystemMetrics(SM_CXICON
int cyIcon = GetSystemMetrics(SM_CYICON
CRect rect;
GetClientRect(&rect);
int x = (rect.Width() - cxIcon + 1) / 2;
int y = (rect.Height() - cyIcon + 1) / 2;
// Draw the icon
dc.DrawIcon(x, y, m_hIcon);
}
else
{
CDialog::OnPaint();
}
}
// The system calls this function to obtain the cursor to display while the user drags
// the minimized window.
HCURSOR CTestCallDlg::OnQueryDragI
{
return static_cast<HCURSOR>(m_hIc
}
ASKER CERTIFIED SOLUTION
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and be sure, to reset the constructor, as it was created from the wizard, something like this:
// This is the constructor of a class that has been exported.
// see TESTDLL.h for the class definition
CTESTDLL::CTESTDLL()
{
}
ike
// This is the constructor of a class that has been exported.
// see TESTDLL.h for the class definition
CTESTDLL::CTESTDLL()
{
}
ike
did you link your library to the test-project?
go to project-settings/linker and add your .lib - file to the project ...
ike
go to project-settings/linker and add your .lib - file to the project ...
ike
what are the errors, please post them here ...
ike