m_msgCur in Visual Studio 2019 - visual-studio

Question

I'm currently transferring old source code to Visual Studio 2019.
The original code is from VC++6 or older.
In Windows MFC, there is a class called CWinThread, and according to the old source code, m_msgCur exists in the class. However, in VS2019, it says that m_msgCur does not exist. Then I found that m_msgCur existed long ago (https://github.com/dblock/msiext/blob/master/externals/WinDDK/7600.16385.1/inc/mfc42/afxwin.h, MFC 4.2) and it is deleted in VS2019. MSG m_msgCur contains current message of the thread, but is there any alternative variable in VS2019?
// message pump for Run
MSG m_msgCur; // current message
Edited:
Project link: https://github.com/ValveSoftware/halflife/tree/master/utils/serverctrl
Class CServerCtrlDlg (inherited from CDialog) is declared in ServerCtrlDlg.h. ServerCtrlDlg.cpp contains how it works. ServerCtrlClg.cpp includes <afxpriv.h>, and <afxpriv.h> contains afxwin.h, which has CWinThread.
Part of ServerCtrlDlg that uses m_msgCur
int CServerCtrlDlg::RunModalLoop(DWORD dwFlags)
{
ASSERT(::IsWindow(m_hWnd)); // window must be created
ASSERT(!(m_nFlags & WF_MODALLOOP)); // window must not already be in modal state
// for tracking the idle time state
BOOL bIdle = TRUE;
LONG lIdleCount = 0;
BOOL bShowIdle = (dwFlags & MLF_SHOWONIDLE) && !(GetStyle() & WS_VISIBLE);
HWND hWndParent = ::GetParent(m_hWnd);
m_nFlags |= (WF_MODALLOOP|WF_CONTINUEMODAL);
MSG* pMsg = &AfxGetThread()->m_msgCur;
// acquire and dispatch messages until the modal state is done
for (;;)
{
ASSERT(ContinueModal());
int iRet = RMLPreIdle();
if (iRet < 0)
goto ExitModal;
else if (iRet > 0)
continue;
// phase1: check to see if we can do idle work
while (bIdle &&
!::PeekMessage(pMsg, NULL, NULL, NULL, PM_NOREMOVE))
{
ASSERT(ContinueModal());
// show the dialog when the message queue goes idle
if (bShowIdle)
{
ShowWindow(SW_SHOWNORMAL);
UpdateWindow();
bShowIdle = FALSE;
}
// call OnIdle while in bIdle state
if (!(dwFlags & MLF_NOIDLEMSG) && hWndParent != NULL && lIdleCount == 0)
{
// send WM_ENTERIDLE to the parent
::SendMessage(hWndParent, WM_ENTERIDLE, MSGF_DIALOGBOX, (LPARAM)m_hWnd);
}
if ((dwFlags & MLF_NOKICKIDLE) ||
!SendMessage(WM_KICKIDLE, MSGF_DIALOGBOX, lIdleCount++))
{
// stop idle processing next time
bIdle = FALSE;
}
}
// phase2: pump messages while available
do
{
BOOL ShouldPump = TRUE;
ASSERT(ContinueModal());
// See if we are requiring messages to be in queue?
if ( m_bOnlyPumpIfMessageInQueue )
{
// If there isn't a message, don't turn over control to PumpMessage
// since it will block
if ( !::PeekMessage( pMsg, NULL, NULL, NULL, PM_NOREMOVE ) )
{
ShouldPump = FALSE;
}
}
// pump message, but quit on WM_QUIT
if ( ShouldPump )
{
if (!AfxGetThread()->PumpMessage())
{
AfxPostQuitMessage(0);
return -1;
}
// show the window when certain special messages rec'd
if (bShowIdle &&
(pMsg->message == 0x118 || pMsg->message == WM_SYSKEYDOWN))
{
ShowWindow(SW_SHOWNORMAL);
UpdateWindow();
bShowIdle = FALSE;
}
if (!ContinueModal())
goto ExitModal;
// reset "no idle" state after pumping "normal" message
if (AfxGetThread()->IsIdleMessage(pMsg))
{
bIdle = TRUE;
lIdleCount = 0;
}
}
} while (::PeekMessage(pMsg, NULL, NULL, NULL, PM_NOREMOVE));
}
ExitModal:
m_nFlags &= ~(WF_MODALLOOP|WF_CONTINUEMODAL);
return m_nModalResult;
}

Answer 1

Short answer is to replace:
MSG* pMsg = &AfxGetThread()->m_msgCur; // vc++ 6
with:
MSG *pMsg = AfxGetCurrentMessage(); // vc++ 2019
A better answer, however, is that if you must hack CWnd::RunModalLoop then you should do it right, and update CServerCtrlDlg::RunModalLoop to base it on the current CWnd::RunModalLoop code from VC++ 2019, instead of the old code borrowed from VC++ 6.
Comparing CServerCtrlDlg::RunModalLoop to the CWnd::RunModalLoop implementation in VC++ 6 from mfc\src\wincore.cpp shows the following lines marked with //++ as having been added.
int CServerCtrlDlg::RunModalLoop(DWORD dwFlags)
{
//...
// acquire and dispatch messages until the modal state is done
for (;;)
{
ASSERT(ContinueModal());
int iRet = RMLPreIdle(); //++
//++
if (iRet < 0) //++
goto ExitModal; //++
else if (iRet > 0) //++
continue; //++
// phase1: check to see if we can do idle work
while (bIdle &&
!::PeekMessage(pMsg, NULL, NULL, NULL, PM_NOREMOVE))
{
ASSERT(ContinueModal());
//...
//...
// phase2: pump messages while available
do
{
ASSERT(ContinueModal());
BOOL ShouldPump = TRUE; //++
//++
// See if we are requiring messages to be in queue? //++
if ( m_bOnlyPumpIfMessageInQueue ) //++
{ //++
// If there isn't a message, don't turn over control to PumpMessage //++
// since it will block //++
if ( !::PeekMessage( pMsg, NULL, NULL, NULL, PM_NOREMOVE ) ) //++
{ //++
ShouldPump = FALSE; //++
} //++
} //++
if ( ShouldPump ) //++
{
/* mfc code executed conditionally */
}
//...
}
CServerCtrlDlg::RunModalLoop should be updated to use the VC++ 2019 CWnd::RunModalLoop code, instead, then those //++ lines merged into it. The MFC changes in CWnd::RunModalLoop are small enough between the two versions that merging is straightforward.