Re: how to pass a this pointer to another class in another file

From:

David Wilkinson <no-reply@effisols.com>

Newsgroups:

microsoft.public.vc.language

Date:

Sat, 26 Apr 2008 06:50:46 -0400

Message-ID:

<ulskft4pIHA.2188@TK2MSFTNGP04.phx.gbl>

Z.K. wrote:

// in TestView.h
class CMyTest;
class CTestView : public XXX
{
CMyTest* m_pMyTest;
};

I tried that, but as soon as I add

#include "MyTest.h"

I get:

c:\Documents and Settings\##########\My Documents\Visual Studio
Projects\Test\MyTest.h(13): error C2143: syntax error : missing ';'
before '*'
c:\Documents and Settings\##########\My Documents\Visual Studio
Projects\Test\MyTest.h(13): error C2501: 'CMyTest::CTestView' : missing
storage-class or type specifiers
c:\Documents and Settings\##########\My Documents\Visual Studio
Projects\Test\MyTest.h(13): error C2501: 'CMyTest::m_pTestView' :
missing storage-class or type specifiers
c:\Documents and Settings\##########\My Documents\Visual Studio
Projects\Test\TestView.cpp(37): error C2039: 'm_pTestView' : is not a
member of 'CMyTest'
        c:\Documents and Settings\##########\My Documents\Visual Studio
Projects\Test\MyTest.h(5) : see declaration of 'CMyTest'
c:\Documents and Settings\##########\My Documents\Visual Studio
Projects\Test\MyTest.h(13): error C2143: syntax error : missing ';'
before '*'
c:\Documents and Settings\##########\My Documents\Visual Studio
Projects\Test\MyTest.h(13): error C2501: 'CMyTest::CTestView' : missing
storage-class or type specifiers
c:\Documents and Settings\##########\My Documents\Visual Studio
Projects\Test\MyTest.h(13): error C2501: 'CMyTest::m_pTestView' :
missing storage-class or type specifiers
c:\Documents and Settings\##########\My Documents\Visual Studio
Projects\Test\MyTest.h(13): error C2143: syntax error : missing ';'
before '*'
c:\Documents and Settings\##########\My Documents\Visual Studio
Projects\Test\MyTest.h(13): error C2501: 'CMyTest::CTestView' : missing
storage-class or type specifiers
c:\Documents and Settings\##########\My Documents\Visual Studio
Projects\Test\MyTest.h(13): error C2501: 'CMyTest::m_pTestView' :
missing storage-class or type specifiers
c:\Documents and Settings\##########\My Documents\Visual Studio
Projects\Test\MyTest.cpp(35): error C2065: 'm_pTestView' : undeclared
identifier
c:\Documents and Settings\##########\My Documents\Visual Studio
Projects\Test\MyTest.cpp(35): error C2227: left of '->m_cstemp' must
point to class/struct/union

TestView.h :

#pragma once

#include "MyTest.h"

class CTestView : public CFormView
{
protected: // create from serialization only
    CTestView();
    DECLARE_DYNCREATE(CTestView)

public:
    enum{ IDD = IDD_TEST_FORM };

// Attributes
public:
    CTestDoc* GetDocument() const;

    CString m_cstemp;


// Operations
public:

// Overrides
    public:
virtual BOOL PreCreateWindow(CREATESTRUCT& cs);
protected:
    virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support
    virtual void OnInitialUpdate(); // called first time after construct

// Implementation
public:
    virtual ~CTestView();
#ifdef _DEBUG
    virtual void AssertValid() const;
    virtual void Dump(CDumpContext& dc) const;
#endif

protected:

// Generated message map functions
protected:
    DECLARE_MESSAGE_MAP()
public:
    afx_msg void OnBnClickedButton1();
    afx_msg void OnBnClickedButton2();
};

#ifndef _DEBUG // debug version in TestView.cpp
inline CTestDoc* CTestView::GetDocument() const
   { return reinterpret_cast<CTestDoc*>(m_pDocument); }
#endif

Z.K:

You did not do what Scott suggested. Just forward declare the class CMyTest in
TestView.h:

// in TestView.h

class CMyTest; // forward declaration

class CTestView : public XXX
{
CMyTest* m_pMyTest;
};

--
David Wilkinson
Visual C++ MVP