Re: VC8, Adding __event to non-CLR code gives error C2712

From:
Edward Diener <eddielee_no_spam_here@tropicsoft.com>
Newsgroups:
microsoft.public.vc.language
Date:
Tue, 02 May 2006 08:50:41 -0400
Message-ID:
<ebXWGcebGHA.1204@TK2MSFTNGP02.phx.gbl>
Marcus Heege wrote:

Hi Edwad,

"Edward Diener" <eddielee_no_spam_here@tropicsoft.com> wrote in message
news:%23ZiWiRabGHA.3632@TK2MSFTNGP05.phx.gbl...

In a non-CLR class I have a number of __events defined. When compiling
the source code in which the corresponding header file has these __events,
I receive the error:

error C2712: Cannot use __try in functions that require object unwinding

pointing to the last of the __event lines in my header file.

When I look at the error message it says:

"cannot use __try in functions that require object unwinding".

Further it is mentioned that "object unwinding" means "destruction".

Needless to say I am not using __try anywhere but perhaps the code being
generated by the __event extended keyword is. I have no idea what the
function that "requires object unwinding" is. How do I resolve this issue
? This problem did not occur for the same code under VC7.1, and frankly I
do not understand why the generated __try keyword can not work with
objects which have destructors.


Re your problem: Can you please post some VC8 code that reproduces the error
and some VC7.1 code that works?


Here is the header file:

===================================================================================

// RegularExpression.h: interface for the RegularExpression class.
//
//////////////////////////////////////////////////////////////////////

#if
!defined(AFX_REGULAREXPRESSION_H__D4133B40_BB9D_11D3_BD0C_000000000000__INCLUDED_)
#define
AFX_REGULAREXPRESSION_H__D4133B40_BB9D_11D3_BD0C_000000000000__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

#include <afx.h>
#include <vector>

#if defined(BUILD_REGULAR_EXPRESSION)
   #define REGULAR_EXPRESSION_IMPORT_EXPORT __declspec(dllexport)
#else
   #define REGULAR_EXPRESSION_IMPORT_EXPORT __declspec(dllimport)
#endif

#pragma pack(push,8)

struct REMatch { CString string; unsigned position; };
typedef std::vector<REMatch> REMatchInfo;

class REGULAR_EXPRESSION_IMPORT_EXPORT RegularExpression : public CObject
{
public:

/* 1) */ __event void OnSearching(RegularExpression *,const REMatchInfo
&,unsigned,unsigned);
/* 2) */ __event void OnChangingFiles(RegularExpression *,CString,const
REMatchInfo &,unsigned,bool &);

   RegularExpression();
   virtual ~RegularExpression();

// Overridables
    virtual void Serialize(CArchive &);

#if defined(_DEBUG)
    // Diagnostic Support
    virtual void AssertValid() const;
    virtual void Dump(CDumpContext &) const;
#endif

private:

DECLARE_SERIAL(RegularExpression)
};

#pragma pack(pop)

#endif //
!defined(AFX_REGULAREXPRESSION_H__D4133B40_BB9D_11D3_BD0C_000000000000__INCLUDED_)

==================================================================================

Here is the source file:

==================================================================================

// RegularExpression.cpp: implementation of the RegularExpression class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "RegularExpression.h"

IMPLEMENT_SERIAL(RegularExpression, CObject, VERSIONABLE_SCHEMA|2)

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

RegularExpression::RegularExpression()

{

}

RegularExpression::~RegularExpression()
{

}

// Overridables

void RegularExpression::Serialize(CArchive& ar)

   {

   CObject::Serialize(ar);

   }

#if defined(_DEBUG)

// Diagnostic Support

void RegularExpression::AssertValid() const

   {

   CObject::AssertValid();

   }

void RegularExpression::Dump(CDumpContext& dc) const

   {

   CObject::Dump(dc);

   }

#endif

===============================================================================

Here are the compiler options in VC7.1 ( VS2003 .NET )

===============================================================================

/Od /D "WIN32" /D "_WINDOWS" /D "_DEBUG" /D "_AFXEXT" /D
"BUILD_REGULAR_EXPRESSION" /D "_WINDLL" /D "_AFXDLL" /D "_MBCS" /Gm
/EHsc /RTC1 /MDd /Yu"stdafx.h"
/Fp"Debug/RegularExpressionComponentDllVc71d.pch" /Fo"Debug/"
/Fd"Debug/vc70.pdb" /W3 /nologo /c /Wp64 /ZI /TP

===============================================================================

Here are the compiler options in VC8 ( VS2005 )

===============================================================================

/Od /D "WIN32" /D "_WINDOWS" /D "_DEBUG" /D "_AFXEXT" /D
"BUILD_REGULAR_EXPRESSION" /D "_WINDLL" /D "_AFXDLL" /D "_MBCS" /Gm
/EHsc /RTC1 /MDd /Yu"stdafx.h"
/Fp"Debug\RegularExpressionComponentDllVc8d.pch" /Fo"Debug\\"
/Fd"Debug\vc80.pdb" /W3 /nologo /c /Wp64 /ZI /TP /errorReport:prompt

===============================================================================

In both VC7.1 and VC8 I create an MFC DLL as an MFC extension DLL.

In VC7.1 the source file will compile without error.

In VC8 I get the error C2712: Cannot use __try in functions that require
object unwinding. It points to the line marked as /* 2) */ in the header
file above. If I eliminate that line, the first __event line, marked as
/* 1) */ does not give an error. I suspect it is because CString must be
  deleted in the generated __try block. However this error does not
occur in VC7.1 . If I change the CString parameter to const CString &
the error goes away. However I am loath to do this for my events because
I will be breaking, even ever so slightly, backward compatibility for my
library.

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