DLL export
in [Visual C]
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From: worlman385 on 26 Mar 2008 21:12 for creating a DLL in VC++ 2005, what's the following do? is it a must have? #ifdef _USRDLL #define EPGLIB_API __declspec( dllexport ) #else /* _USRDLL */ #define EPGLIB_API __declspec( dllimport ) #endif /* _USRDLL */ ====================== for each function that' call by DLL user, I must add PROJECTName_API + return type + PASCAL + functionName like follows? why related to PSCAL?? EPGLIB_API BOOL PASCAL CreateEPGLibInstance(); EPGLIB_API HRESULT PASCAL LoadXMLData(LPCTSTR tszXMLFileName); EPGLIB_API HRESULT PASCAL PostSoapRequest(); ====================== // EPGLib.h : main header file for the EPGLib DLL // #pragma once #ifndef __AFXWIN_H__ #error "include 'stdafx.h' before including this file for PCH" #endif #include "resource.h" // main symbols // CEPGLibApp // See EPGLib.cpp for the implementation of this class // class CEPGLibApp : public CWinApp { public: CEPGLibApp(); HRESULT LoadXMLData(LPCTSTR tszXMLFileName); // Overrides public: virtual BOOL InitInstance(); virtual int ExitInstance(); DECLARE_MESSAGE_MAP() }; #ifdef _USRDLL #define EPGLIB_API __declspec( dllexport ) #else /* _USRDLL */ #define EPGLIB_API __declspec( dllimport ) #endif /* _USRDLL */ EPGLIB_API BOOL PASCAL CreateEPGLibInstance(); EPGLIB_API HRESULT PASCAL LoadXMLData(LPCTSTR tszXMLFileName); EPGLIB_API HRESULT PASCAL PostSoapRequest();
From: worlman385 on 26 Mar 2008 21:28 When I implement a DLL, should I always have the following 2 function? are these 2 function will load the DLL into memory and unload from memory?? what's CoInitialize(NULL)?? ============================== BOOL CEPGLibApp::InitInstance() { CWinApp::InitInstance(); if (!AfxSocketInit()) { AfxMessageBox(IDP_SOCKETS_INIT_FAILED); return FALSE; } CoInitialize(NULL); return TRUE; } int CEPGLibApp::ExitInstance() { CoUninitialize(); return CWinApp::ExitInstance(); }
From: Dan Bloomquist on 26 Mar 2008 21:05 worlman385(a)yahoo.com wrote: > for creating a DLL in VC++ 2005, what's the following do? is it a must > have? > > #ifdef _USRDLL > #define EPGLIB_API __declspec( dllexport ) > #else /* _USRDLL */ > #define EPGLIB_API __declspec( dllimport ) > #endif /* _USRDLL */ > ====================== That is fine. I don't know if it is more official to use: #ifdef HECRAFT_DLL_COMPILE #define HECRAFT_EXPORT AFX_CLASS_EXPORT #else #define HECRAFT_EXPORT AFX_CLASS_IMPORT #endif > for each function that' call by DLL user, I must add > > PROJECTName_API + return type + PASCAL + functionName like follows? > why related to PSCAL?? > > EPGLIB_API BOOL PASCAL CreateEPGLibInstance(); > EPGLIB_API HRESULT PASCAL LoadXMLData(LPCTSTR tszXMLFileName); > EPGLIB_API HRESULT PASCAL PostSoapRequest(); The PASCAL is unnecessary. My docs say it is obsolete. > > class CEPGLibApp : public CWinApp > { > public: > CEPGLibApp(); > HRESULT LoadXMLData(LPCTSTR tszXMLFileName); > > // Overrides > public: > virtual BOOL InitInstance(); > virtual int ExitInstance(); > > DECLARE_MESSAGE_MAP() > }; > > EPGLIB_API BOOL PASCAL CreateEPGLibInstance(); > EPGLIB_API HRESULT PASCAL LoadXMLData(LPCTSTR tszXMLFileName); > EPGLIB_API HRESULT PASCAL PostSoapRequest(); See TN033 about exporting class members. This won't link as the members look to be declared as globals. You would class A { AFX_EXT_CLASS void Member( ); }; If you don't want to export the whole class. But there is more to it as you are creating a CWinApp. Are you sure that is what you want to do? Best, Dan.
From: Dan Bloomquist on 26 Mar 2008 21:32 worlman385(a)yahoo.com wrote: > When I implement a DLL, should I always have the following 2 function? > > are these 2 function will load the DLL into memory and unload from > memory?? > > what's CoInitialize(NULL)?? You could put that in the VS search or google. Short answer, no. CEPGLibApp came up on a search in a thread started by 'June Lee' on the 21st, same members. In June's code there is a COM object, so yes. Me thinks you have a plate full if June is gone and now it is your job... Best, Dan.
From: Joseph M. Newcomer on 26 Mar 2008 23:03
See below On Wed, 26 Mar 2008 17:12:13 -0800, worlman385(a)yahoo.com wrote: >for creating a DLL in VC++ 2005, what's the following do? is it a must >have? > >#ifdef _USRDLL >#define EPGLIB_API __declspec( dllexport ) >#else /* _USRDLL */ >#define EPGLIB_API __declspec( dllimport ) >#endif /* _USRDLL */ >====================== > >for each function that' call by DLL user, I must add > >PROJECTName_API + return type + PASCAL + functionName like follows? >why related to PSCAL?? > >EPGLIB_API BOOL PASCAL CreateEPGLibInstance(); >EPGLIB_API HRESULT PASCAL LoadXMLData(LPCTSTR tszXMLFileName); >EPGLIB_API HRESULT PASCAL PostSoapRequest(); **** PASCAL should *never* be used; it died with Win16, and its appearance in Win32 is always an error. You can use WINAPI or CALLBACK or one of the other representatives of __stdcall if you wish, but none of these are actually required. But yes, you have the right idea here. I would not use the _USRDLL flag for this purpose, I would use a name of my own referring to my header file and my project, because if a DLL is calling another DLL, the _USRDLL will be defined for the caller as well as the called. **** > >====================== > >// EPGLib.h : main header file for the EPGLib DLL >// > >#pragma once > >#ifndef __AFXWIN_H__ > #error "include 'stdafx.h' before including this file for PCH" >#endif > >#include "resource.h" // main symbols > > >// CEPGLibApp >// See EPGLib.cpp for the implementation of this class >// > >class CEPGLibApp : public CWinApp >{ >public: > CEPGLibApp(); > HRESULT LoadXMLData(LPCTSTR tszXMLFileName); > >// Overrides >public: > virtual BOOL InitInstance(); > virtual int ExitInstance(); > > DECLARE_MESSAGE_MAP() >}; > > >#ifdef _USRDLL >#define EPGLIB_API __declspec( dllexport ) >#else /* _USRDLL */ >#define EPGLIB_API __declspec( dllimport ) >#endif /* _USRDLL */ > >EPGLIB_API BOOL PASCAL CreateEPGLibInstance(); >EPGLIB_API HRESULT PASCAL LoadXMLData(LPCTSTR tszXMLFileName); >EPGLIB_API HRESULT PASCAL PostSoapRequest(); **** Delete every occurrence of PASCAL, either replacing it with something that was not made obsolete in 1992 or not using it at all. Change _USRDLL to a symbol you define in your DLL before doing the #include of your header file. joe **** Joseph M. Newcomer [MVP] email: newcomer(a)flounder.com Web: http://www.flounder.com MVP Tips: http://www.flounder.com/mvp_tips.htm |