Trying to dynamically load a class at rutime from DLL

[garywillams]

Hi,

I am new to coding with macros. I have this code and I am trying to run this by dynamically loading a class from a DLL.

#pragma once
#ifndef DLLEXPORTS_H
#define DLLEXPORTS_H
#ifdef _LoadPCDigDlls_h_
#define _LoadPCDigDlls_h_
#define CALLBACK __stdcall
#define IFC_IMP_DLL  __declspec(dllimport)
#endif //_LoadPCDigDlls_h_

#define IFCAPI __stdcall
#define IFCCALL IFC_IMP_DLL IFCAPI

typedef enum {
	IFC_CAP_MBOARD,		// Image Capture motherboard, e.g., IC-PCI,PCVision
	IFC_MNG_MBOARD,		// Image Manager motherboard, e.g., IM-PCI
	IFC_CMC_MBOARD,		// Computational module motherboard, e.g., CMC-PCI
	IFC_AM_DBOARD,
	IFC_CM_DBOARD,
	IFC_DM_DBOARD,
	IFC_NUM_BOARD_KINDS
} IFC_BOARD_KIND;

#define IFC_ACTIVE_CAMERA_FLAG 0x8000
typedef unsigned char    * pBYTE;  
#define IFC_INFINITE_FRAMES -1
typedef void *HIFCGRAB;


class IFC_IMP_DLL CIobject
{
public:

// Object model (types, destruction, allocation)
	virtual ~CIobject();  // virtual destructors are necessary

#ifdef new
#define _IFC_SAVE_NEW_
#undef new
#endif
	void* IFCAPI operator new(size_t nSize);
	void* IFCAPI operator new(size_t nSize,void* p);
	void  IFCAPI operator delete(void* p);
#if _MSC_VER >= 1200
	void IFCAPI operator delete(void* p, void* pPlace);
#endif

	// for file name/line number tracking using DEBUG_NEW
	void* IFCAPI operator new(size_t nSize, LPCSTR lpszFileName, int nLine);

#if _MSC_VER >= 1200
	void IFCAPI operator delete(void* p, LPCSTR lpszFileName, int nLine);
#endif

#if defined(_IFC_SAVE_NEW_) && defined(_DEBUG) && defined(DEBUG_NEW)
#define new DEBUG_NEW
#endif
#ifdef _IFC_SAVE_NEW_
#undef _IFC_SAVE_NEW_
#endif


	// Disable the copy constructor and assignment by default so you will get
	//   compiler errors instead of unexpected behaviour if you pass objects
	//   by value or assign objects.
protected:
	CIobject();
private:
	CIobject(const CIobject& objectSrc);              // no implementation
	void operator=(const CIobject& objectSrc);       // no implementation
};

class IFC_IMP_DLL CModule : public CIobject 
{
public:
		CModule();
	virtual ~CModule();
};

class IFC_IMP_DLL CParentMod : public CModule  
{
public:
	CParentMod();
	virtual ~CParentMod();
};


typedef CParentMod * PCParentMod;

typedef PCParentMod  (CALLBACK* LPIfxCreateParentModule)(IFC_BOARD_KIND modKind, DWORD modSubkind, DWORD seqnum, char *cfgFile=NULL, BOOL inspectOnly=FALSE);
typedef PCParentMod  (CALLBACK* LPIfxCreateCaptureModule)(char *modName,DWORD seqnum, char *cfgFile);
typedef void (IFC_IMP_DLL* LPProcessCameraFilesInDir)(const pSTRING szPath, BOOL bRecurse = FALSE);
typedef BOOL (IFC_IMP_DLL* LPEnableJitGrabMemLock)(void);
typedef CICamera (IFC_IMP_DLL* LPGetCam)(DWORD camPortNum=IFC_ACTIVE_CAMERA_FLAG);
typedef HIFCGRAB (IFC_IMP_DLL* LPGrab)(DWORD dwOptions,pBYTE dest, int ringNumFrames,int totalNumFrames=IFC_INFINITE_FRAMES, int x=0, int y=0, int dx=0, int dy=0);
typedef BOOL (IFC_IMP_DLL* LPFreeze)(CIFrame *frame);
typedef int (IFC_IMP_DLL* LPGrabWaitFrameEx)(HIFCGRAB grabID, BYTE **frameAddr=NULL, int FrameSeqNum=IFC_WAIT_NEWER_FRAME, DWORD milliseconds=IFC_WAIT_FOREVER, BOOL lock=TRUE,DWORD *acquiredDy=NULL, BOOL *VirtualFrameEnd=NULL, GRAB_EXT_ATTR *ExtendedAttr=NULL);
typedef void (IFC_IMP_DLL* LPGrabRelease)(HIFCGRAB grabID, int seqNum);
typedef void (IFC_IMP_DLL* LPGetAttr)(LPCAM_ATTR lpAttr, BOOL zoomCorrected=TRUE);

extern LPIfxCreateParentModule IfxCreateParentModule;
extern LPIfxCreateCaptureModule IfxCreateCaptureModule;
extern LPProcessCameraFilesInDir ProcessCameraFilesInDir;
extern LPEnableJitGrabMemLock EnableJitGrabMemLock;
extern LPGetCam GetCam;
extern LPGrab Grab;
extern LPFreeze Freeze;
extern LPGrabWaitFrameEx GrabWaitFrameEx;
extern LPGrabRelease GrabRelease;
extern LPGetAttr GetAttr;

extern int LoadPCDigDlls();
extern int FreePCDigDlls();

When I build the solution I am getting these errors

1>------ Build started: Project: sprayQC, Configuration: Debug Win32 ------
1>Compiling...
1>LoadPCDigDlls.cpp
1>c:\projects\sprayqc2601\loadpcdigdlls.h(92) : error C2383: 'LPIfxCreateParentModule' : default-arguments are not allowed on this symbol
1>c:\projects\sprayqc2601\loadpcdigdlls.h(94) : error C2059: syntax error : '__declspec(dllimport)'
1>c:\projects\sprayqc2601\loadpcdigdlls.h(95) : error C2059: syntax error : '__declspec(dllimport)'
1>c:\projects\sprayqc2601\loadpcdigdlls.h(96) : warning C4042: 'LPGetCam' : has bad storage class
1>c:\projects\sprayqc2601\loadpcdigdlls.h(96) : error C2091: function returns function
1>c:\projects\sprayqc2601\loadpcdigdlls.h(96) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\projects\sprayqc2601\loadpcdigdlls.h(97) : error C2059: syntax error : '__declspec(dllimport)'
1>c:\projects\sprayqc2601\loadpcdigdlls.h(98) : error C2059: syntax error : '__declspec(dllimport)'
1>c:\projects\sprayqc2601\loadpcdigdlls.h(99) : error C2059: syntax error : '__declspec(dllimport)'
1>c:\projects\sprayqc2601\loadpcdigdlls.h(100) : error C2059: syntax error : '__declspec(dllimport)'
1>c:\projects\sprayqc2601\loadpcdigdlls.h(101) : error C2059: syntax error : '__declspec(dllimport)'
1>c:\projects\sprayqc2601\loadpcdigdlls.h(105) : error C2146: syntax error : missing ';' before identifier 'ProcessCameraFilesInDir'
1>c:\projects\sprayqc2601\loadpcdigdlls.h(105) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\projects\sprayqc2601\loadpcdigdlls.h(105) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\projects\sprayqc2601\loadpcdigdlls.h(106) : error C2146: syntax error : missing ';' before identifier 'EnableJitGrabMemLock'
1>c:\projects\sprayqc2601\loadpcdigdlls.h(106) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\projects\sprayqc2601\loadpcdigdlls.h(106) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\projects\sprayqc2601\loadpcdigdlls.h(107) : error C2146: syntax error : missing ';' before identifier 'GetCam'
1>c:\projects\sprayqc2601\loadpcdigdlls.h(107) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\projects\sprayqc2601\loadpcdigdlls.h(107) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\projects\sprayqc2601\loadpcdigdlls.h(108) : error C2146: syntax error : missing ';' before identifier 'Grab'
1>c:\projects\sprayqc2601\loadpcdigdlls.h(108) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\projects\sprayqc2601\loadpcdigdlls.h(108) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\projects\sprayqc2601\loadpcdigdlls.h(109) : error C2146: syntax error : missing ';' before identifier 'Freeze'
1>c:\projects\sprayqc2601\loadpcdigdlls.h(109) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\projects\sprayqc2601\loadpcdigdlls.h(109) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\projects\sprayqc2601\loadpcdigdlls.h(110) : error C2146: syntax error : missing ';' before identifier 'GrabWaitFrameEx'
1>c:\projects\sprayqc2601\loadpcdigdlls.h(110) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\projects\sprayqc2601\loadpcdigdlls.h(110) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\projects\sprayqc2601\loadpcdigdlls.h(111) : error C2146: syntax error : missing ';' before identifier 'GrabRelease'
1>c:\projects\sprayqc2601\loadpcdigdlls.h(111) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\projects\sprayqc2601\loadpcdigdlls.h(111) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\projects\sprayqc2601\loadpcdigdlls.h(112) : error C2146: syntax error : missing ';' before identifier 'GetAttr'
1>c:\projects\sprayqc2601\loadpcdigdlls.h(112) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\projects\sprayqc2601\loadpcdigdlls.h(112) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\projects\sprayqc2601\loadpcdigdlls.h(116) : fatal error C1070: mismatched #if/#endif pair in file 'c:\projects\sprayqc2601\loadpcdigdlls.h'
1>Build log was saved at "file://c:\Projects\sprayQC2601\Debug\BuildLog.htm"
1>sprayQC - 35 error(s), 1 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

Somebody please help me.

Thanks in advance.
Edit/Delete Message

[vijayan]

this header is an absolute mess. it should not compile on any conforming compiler. the major errors are:

1. default values for parameters are not allowed in a typedef (or in a pointer to a function)
2. you can import variables and functions from a dll, but not a typedef (a typedef is required at compile-time.)
3. use of types that have not been declared

with these corrected, the header would compile. but you must be a very brave programmer if you decide to use it (trust the idiot who wrote this header).

#pragma once
#ifndef DLLEXPORTS_H
#define DLLEXPORTS_H
#ifdef _LoadPCDigDlls_h_
#define _LoadPCDigDlls_h_
#define CALLBACK __stdcall
#define IFC_IMP_DLL  __declspec(dllimport)
#endif //_LoadPCDigDlls_h_

#define IFCAPI __stdcall
#define IFCCALL IFC_IMP_DLL IFCAPI

typedef enum {
	IFC_CAP_MBOARD,		// Image Capture motherboard, e.g., IC-PCI,PCVision
	IFC_MNG_MBOARD,		// Image Manager motherboard, e.g., IM-PCI
	IFC_CMC_MBOARD,		// Computational module motherboard, e.g., CMC-PCI
	IFC_AM_DBOARD,
	IFC_CM_DBOARD,
	IFC_DM_DBOARD,
	IFC_NUM_BOARD_KINDS
} IFC_BOARD_KIND;

#define IFC_ACTIVE_CAMERA_FLAG 0x8000
typedef unsigned char    * pBYTE;  
#define IFC_INFINITE_FRAMES -1
typedef void *HIFCGRAB;


class IFC_IMP_DLL CIobject
{
public:

// Object model (types, destruction, allocation)
	virtual ~CIobject();  // virtual destructors are necessary

#ifdef new
#define _IFC_SAVE_NEW_
#undef new
#endif
	void* IFCAPI operator new(size_t nSize);
	void* IFCAPI operator new(size_t nSize,void* p);
	void  IFCAPI operator delete(void* p);
#if _MSC_VER >= 1200
	void IFCAPI operator delete(void* p, void* pPlace);
#endif

	// for file name/line number tracking using DEBUG_NEW
	void* IFCAPI operator new(size_t nSize, LPCSTR lpszFileName, int nLine);

#if _MSC_VER >= 1200
	void IFCAPI operator delete(void* p, LPCSTR lpszFileName, int nLine);
#endif

#if defined(_IFC_SAVE_NEW_) && defined(_DEBUG) && defined(DEBUG_NEW)
#define new DEBUG_NEW
#endif
#ifdef _IFC_SAVE_NEW_
#undef _IFC_SAVE_NEW_
#endif


	// Disable the copy constructor and assignment by default so you will get
	//   compiler errors instead of unexpected behaviour if you pass objects
	//   by value or assign objects.
protected:
	CIobject();
private:
	CIobject(const CIobject& objectSrc);              // no implementation
	void operator=(const CIobject& objectSrc);       // no implementation
};

class IFC_IMP_DLL CModule : public CIobject 
{
public:
		CModule();
	virtual ~CModule();
};

class IFC_IMP_DLL CParentMod : public CModule  
{
public:
	CParentMod();
	virtual ~CParentMod();
};


typedef CParentMod * PCParentMod;

////////////////////////////////////////////////////////
// the following declaraions are required. replace these 
// by including the header files containing the declarations
////////////////////////////////////////////////////////
class CICamera ;
class CIFrame;
class GRAB_EXT_ATTR;
class LPCAM_ATTR;
///////////////////////////////////////

typedef PCParentMod  (CALLBACK* LPIfxCreateParentModule)(IFC_BOARD_KIND modKind, DWORD modSubkind, DWORD seqnum, char *cfgFile, BOOL inspectOnly);
typedef PCParentMod  (CALLBACK* LPIfxCreateCaptureModule)(char *modName,DWORD seqnum, char *cfgFile);
typedef void (CALLBACK* LPProcessCameraFilesInDir)(const PSTR szPath, BOOL bRecurse );
typedef BOOL (CALLBACK* LPEnableJitGrabMemLock)(void);
typedef CICamera (CALLBACK* LPGetCam)(DWORD camPortNum);
typedef HIFCGRAB (CALLBACK* LPGrab)(DWORD dwOptions,pBYTE dest, int ringNumFrames,int totalNumFrames, int x, int y, int dx, int dy);
typedef BOOL (CALLBACK* LPFreeze)(CIFrame *frame);
typedef int (CALLBACK* LPGrabWaitFrameEx)(HIFCGRAB grabID, BYTE **frameAddr, int FrameSeqNum, DWORD milliseconds, BOOL lock,DWORD *acquiredDy, BOOL *VirtualFrameEnd, GRAB_EXT_ATTR *ExtendedAttr);
typedef void (CALLBACK* LPGrabRelease)(HIFCGRAB grabID, int seqNum);
typedef void (CALLBACK* LPGetAttr)(LPCAM_ATTR lpAttr, BOOL zoomCorrected);

extern IFC_IMP_DLL LPIfxCreateParentModule IfxCreateParentModule;
extern IFC_IMP_DLL LPIfxCreateCaptureModule IfxCreateCaptureModule;
extern IFC_IMP_DLL LPProcessCameraFilesInDir ProcessCameraFilesInDir;
extern IFC_IMP_DLL LPEnableJitGrabMemLock EnableJitGrabMemLock;
extern IFC_IMP_DLL LPGetCam GetCam;
extern IFC_IMP_DLL LPGrab Grab;
extern IFC_IMP_DLL LPFreeze Freeze;
extern IFC_IMP_DLL LPGrabWaitFrameEx GrabWaitFrameEx;
extern IFC_IMP_DLL LPGrabRelease GrabRelease;
extern IFC_IMP_DLL LPGetAttr GetAttr;

extern int LoadPCDigDlls();
extern int FreePCDigDlls();
#endif // DLLEXPORTS_H

[garywillams]

Thanks for the reply. I trust you and yeah I know its a big mess. I am trying to clear it. It might take some time but I am sure that I will clear it.

I have been given strict instructions that, I am not allowed to include any header files, instead write all the necessary classes in the same header file.

Thanks again.