1、创建和l止U程 在MFCE序中创Z个线E，宜调用AfxBeginThread函数。该函数因参C同而具有两U重载版本，分别对应工作者线E和用户接口QUIQ线E?br /> 工作者线E?br /> CWinThread *AfxBeginThread(
AFX_THREADPROC pfnThreadProc, //控制函数
LPVOID pParam, //传递给控制函数的参?br /> int nPriority = THREAD_PRIORITY_NORMAL, //U程的优先
UINT nStackSize = 0, //U程的堆栈大?br /> DWORD dwCreateFlags = 0, //U程的创建标?br /> LPSECURITY_ATTRIBUTES lpSecurityAttrs = NULL //U程的安全属?br />); |
工作者线E编E较为简单，只需~写U程控制函数和启动线E即可。下面的代码l出了定义一个控制函数和启动它的q程Q?br /> //U程控制函数
UINT MfcThreadProc(LPVOID lpParam)
{
CExampleClass *lpObject = (CExampleClass*)lpParam;
if (lpObject == NULL || !lpObject->IsKindof(RUNTIME_CLASS(CExampleClass)))
return - 1; //输入参数非法
//U程成功启动
while (1)
{
...//
}
return 0;
}
//在MFCE序中启动线E?br />AfxBeginThread(MfcThreadProc, lpObject); |
UIU程 创徏用户界面U程Ӟ必须首先从CWinThread zc，q?DECLARE_DYNCREATE ?IMPLEMENT_DYNCREATE 宏声明此cR?br /> 下面l出了CWinThreadcȝ原型Q添加了关于光要函数功能和是否需要被l承c重载的注释Q： class CWinThread : public CCmdTarget
{
DECLARE_DYNAMIC(CWinThread)
public:
// Constructors
CWinThread();
BOOL CreateThread(DWORD dwCreateFlags = 0, UINT nStackSize = 0,
LPSECURITY_ATTRIBUTES lpSecurityAttrs = NULL);
// Attributes
CWnd* m_pMainWnd; // main window (usually same AfxGetApp()->m_pMainWnd)
CWnd* m_pActiveWnd; // active main window (may not be m_pMainWnd)
BOOL m_bAutoDelete; // enables 'delete this' after thread termination
// only valid while running
HANDLE m_hThread; // this thread's HANDLE
operator HANDLE() const;
DWORD m_nThreadID; // this thread's ID
int GetThreadPriority();
BOOL SetThreadPriority(int nPriority);
// Operations
DWORD SuspendThread();
DWORD ResumeThread();
BOOL PostThreadMessage(UINT message, WPARAM wParam, LPARAM lParam);
// Overridables
//执行U程实例初始化，必须重写
virtual BOOL InitInstance();
// running and idle processing
//控制U程的函敎ͼ包含消息泵，一般不重写
virtual int Run();
//消息调度到TranslateMessage和DispatchMessage之前对其q行{选，
//通常不重?br /> virtual BOOL PreTranslateMessage(MSG* pMsg);
virtual BOOL PumpMessage(); // low level message pump
//执行U程特定的闲|时间处理，通常不重?br /> virtual BOOL OnIdle(LONG lCount); // return TRUE if more idle processing
virtual BOOL IsIdleMessage(MSG* pMsg); // checks for special messages
//U程l止时执行清除，通常需要重?br /> virtual int ExitInstance(); // default will 'delete this'
//截获qE的消息和命令处理程序引发的未处理异常，通常不重?br /> virtual LRESULT ProcessWndProcException(CException* e, const MSG* pMsg);
// Advanced: handling messages sent to message filter hook
virtual BOOL ProcessMessageFilter(int code, LPMSG lpMsg);
// Advanced: virtual access to m_pMainWnd
virtual CWnd* GetMainWnd();
// Implementation
public:
virtual ~CWinThread();
#ifdef _DEBUG
virtual void AssertValid() const;
virtual void Dump(CDumpContext& dc) const;
int m_nDisablePumpCount; // Diagnostic trap to detect illegal re-entrancy
#endif
void CommonConstruct();
virtual void Delete();
// 'delete this' only if m_bAutoDelete == TRUE
// message pump for Run
MSG m_msgCur; // current message
public:
// constructor used by implementation of AfxBeginThread
CWinThread(AFX_THREADPROC pfnThreadProc, LPVOID pParam);
// valid after construction
LPVOID m_pThreadParams; // generic parameters passed to starting function
AFX_THREADPROC m_pfnThreadProc;
// set after OLE is initialized
void (AFXAPI* m_lpfnOleTermOrFreeLib)(BOOL, BOOL);
COleMessageFilter* m_pMessageFilter;
protected:
CPoint m_ptCursorLast; // last mouse position
UINT m_nMsgLast; // last mouse message
BOOL DispatchThreadMessageEx(MSG* msg); // helper
void DispatchThreadMessage(MSG* msg); // obsolete
};
|
启动UIU程的AfxBeginThread函数的原型ؓQ?br /> CWinThread *AfxBeginThread(
//从CWinThreadz的类?RUNTIME_CLASS
CRuntimeClass *pThreadClass,
int nPriority = THREAD_PRIORITY_NORMAL,
UINT nStackSize = 0,
DWORD dwCreateFlags = 0,
LPSECURITY_ATTRIBUTES lpSecurityAttrs = NULL
); |
我们可以方便C用VC++ 6.0cd导定义一个承自CWinThread的用LE类。下面给Z生我们自定义的CWinThread子类CMyUIThread的方法?br /> 打开VC++ 6.0cd|在如下窗口中选择Base ClasscMؓCWinThreadQ输入子cd为CMyUIThreadQ点?OK"按钮后就产生了类CMyUIThread?br /> 其源代码框架为： /////////////////////////////////////////////////////////////////////////////
// CMyUIThread thread
class CMyUIThread : public CWinThread
{
DECLARE_DYNCREATE(CMyUIThread)
protected:
CMyUIThread(); // protected constructor used by dynamic creation
// Attributes
public:
// Operations
public:
// Overrides
// ClassWizard generated virtual function overrides
//{{AFX_VIRTUAL(CMyUIThread)
public:
virtual BOOL InitInstance();
virtual int ExitInstance();
//}}AFX_VIRTUAL
// Implementation
protected:
virtual ~CMyUIThread();
// Generated message map functions
//{{AFX_MSG(CMyUIThread)
// NOTE - the ClassWizard will add and remove member functions here.
//}}AFX_MSG
DECLARE_MESSAGE_MAP()
};
/////////////////////////////////////////////////////////////////////////////
// CMyUIThread
IMPLEMENT_DYNCREATE(CMyUIThread, CWinThread)
CMyUIThread::CMyUIThread()
{}
CMyUIThread::~CMyUIThread()
{}
BOOL CMyUIThread::InitInstance()
{
// TODO: perform and per-thread initialization here
return TRUE;
}
int CMyUIThread::ExitInstance()
{
// TODO: perform any per-thread cleanup here
return CWinThread::ExitInstance();
}
BEGIN_MESSAGE_MAP(CMyUIThread, CWinThread)
//{{AFX_MSG_MAP(CMyUIThread)
// NOTE - the ClassWizard will add and remove mapping macros here.
//}}AFX_MSG_MAP
END_MESSAGE_MAP() |
使用下列代码可以启动这个UIU程Q?br /> CMyUIThread *pThread;
pThread = (CMyUIThread*)
AfxBeginThread( RUNTIME_CLASS(CMyUIThread) ); |
另外Q我们也可以不用AfxBeginThread 创徏U程Q而是分如下两步完成： Q?Q调用线E类的构造函数创Z个线E对象； Q?Q调用CWinThread::CreateThread函数来启动该U程?br /> 在线E自w内调用AfxEndThread函数可以l止该线E： void AfxEndThread(
UINT nExitCode //the exit code of the thread
); |
对于UIU程而言Q如果消息队列中攑օ了WM_QUIT消息Q将l束U程?br /> 关于UIU程和工作者线E的分配Q最好的做法是：所有与UI相关的操作放入主U程Q其它的Ua的运工作交l独立的C工作者线E?br /> 候捷先生早些旉喜欢为MDIE序的每个窗口创Z个线E，他后来澄清了q个错误。因为如果ؓMDIE序的每个窗口都单独创徏一个线E，在窗口进行切换的时候，进行线E的上下文切换！ 2.U程间通信 MFC中定义了l承自CSyncObjectcȝCCriticalSection
、CCEvent、CMutex、CSemaphorecd装和化了WIN32
API所提供的界区、事件、互斥和信号量。用这些同步机Ӟ必须包含"Afxmt.h"头文件。下囄Zcȝl承关系Q?br /> 作ؓCSyncObjectcȝl承c，我们仅仅使用基类CSyncObject的接口函数就可以方便、统一的操作CCriticalSection 、CCEvent、CMutex、CSemaphorec，下面是CSyncObjectcȝ原型Q?br /> class CSyncObject : public CObject
{
DECLARE_DYNAMIC(CSyncObject)
// Constructor
public:
CSyncObject(LPCTSTR pstrName);
// Attributes
public:
operator HANDLE() const;
HANDLE m_hObject;
// Operations
virtual BOOL Lock(DWORD dwTimeout = INFINITE);
virtual BOOL Unlock() = 0;
virtual BOOL Unlock(LONG /* lCount */, LPLONG /* lpPrevCount=NULL */)
{ return TRUE; }
// Implementation
public:
virtual ~CSyncObject();
#ifdef _DEBUG
CString m_strName;
virtual void AssertValid() const;
virtual void Dump(CDumpContext& dc) const;
#endif
friend class CSingleLock;
friend class CMultiLock;
}; |
CSyncObjectcL主要的两个函数是Lock和UnlockQ若我们直接使用CSyncObjectcd其派生类Q我们需要非常小心地在Lock之后调用Unlock?br /> MFC提供的另两个cCSingleLockQ等待一个对象）和CMultiLockQ等待多个对象）为我们编写应用程序提供了更灵zȝ机制Q下面以实际来阐qCSingleLock的用法： class CThreadSafeWnd
{
public:
CThreadSafeWnd(){}
~CThreadSafeWnd(){}
void SetWindow(CWnd *pwnd)
{
m_pCWnd = pwnd;
}
void PaintBall(COLORREF color, CRect &rc);
private:
CWnd *m_pCWnd;
CCriticalSection m_CSect;
};
void CThreadSafeWnd::PaintBall(COLORREF color, CRect &rc)
{
CSingleLock csl(&m_CSect);
//~省的Timeout是INFINITEQ只有m_Csect被激z，csl.Lock()才能q回
//trueQ这里一直等?br /> if (csl.Lock())
;
{
// not necessary
//AFX_MANAGE_STATE(AfxGetStaticModuleState( ));
CDC *pdc = m_pCWnd->GetDC();
CBrush brush(color);
CBrush *oldbrush = pdc->SelectObject(&brush);
pdc->Ellipse(rc);
pdc->SelectObject(oldbrush);
GdiFlush(); // don't wait to update the display
}
} |
上述实例讲述了用CSingleLock对Windows GDI相关对象q行保护的方法，下面再给Z个其他方面的例子Q?br /> int array1[10], array2[10];
CMutexSection section; //创徏一个CMutexcȝ对象
//赋值线E控制函?br />UINT EvaluateThread(LPVOID param)
{
CSingleLock singlelock;
singlelock(§ion);
//互斥区域
singlelock.Lock();
for (int i = 0; i < 10; i++)
array1[i] = i;
singlelock.Unlock();
}
//拯U程控制函数
UINT CopyThread(LPVOID param)
{
CSingleLock singlelock;
singlelock(§ion);
//互斥区域
singlelock.Lock();
for (int i = 0; i < 10; i++)
array2[i] = array1[i];
singlelock.Unlock();
}
}
AfxBeginThread(EvaluateThread, NULL); //启动赋值线E?br />AfxBeginThread(CopyThread, NULL); //启动拯U程 |
上面的例子中启动了两个线EEvaluateThread和CopyThreadQ线EEvaluateThread?0个数赋值给数组array1
[]Q线ECopyThread数larray1[]拯l数larray2[]。由于数l的拯和赋值都是整体行为，如果不以互斥形式执行代码D： for (int i = 0; i < 10; i++)
array1[i] = i; |
?br /> for (int i = 0; i < 10; i++)
array2[i] = array1[i]; |
其结果是很难预料的！ 除了可用CCriticalSection、CEvent、CMutex、CSemaphore作ؓU程间同步通信的方式以外，我们q可以利用PostThreadMessage函数在线E间发送消息： BOOL PostThreadMessage(DWORD idThread, // thread identifier
UINT Msg, // message to post
WPARAM wParam, // first message parameter
LPARAM lParam // second message parameter
); |
3.U程与消息队?br /> 在WIN32中，每一个线E都对应着一个消息队列。由于一个线E可以生数个窗口，所以ƈ不是每个H口都对应着一个消息队列。下列几句话应该作ؓ"定理"被记住： "定理" 一 所有生给某个H口的消息，都先由创个窗口的U程处理Q?br /> "定理" ?br /> Windows屏幕上的每一个控仉是一个窗口，有对应的H口函数?br /> 消息的发送通常有两U方式，一是SendMessageQ一是PostMessageQ其原型分别为： LRESULT SendMessage(HWND hWnd, // handle of destination window
UINT Msg, // message to send
WPARAM wParam, // first message parameter
LPARAM lParam // second message parameter
);
BOOL PostMessage(HWND hWnd, // handle of destination window
UINT Msg, // message to post
WPARAM wParam, // first message parameter
LPARAM lParam // second message parameter
); |
两个函数原型中的四个参数的意义相同，但是SendMessage和PostMessage的行为有差异。SendMessage必须{待消息被处理后
才返回，而PostMessage仅仅消息放入消息队列。SendMessage的目标窗口如果属于另一个线E，则会发生U程上下文切换，{待另一U程
处理完成消息。ؓ了防止另一U程当掉Q导致SendMessage永远不能q回Q我们可以调用SendMessageTimeout函数Q?br /> LRESULT SendMessageTimeout(
HWND hWnd, // handle of destination window
UINT Msg, // message to send
WPARAM wParam, // first message parameter
LPARAM lParam, // second message parameter
UINT fuFlags, // how to send the message
UINT uTimeout, // time-out duration
LPDWORD lpdwResult // return value for synchronous call
); |
4. MFCU程、消息队列与MFCE序?生死因果" 分析MFCE序的主U程启动及消息队列处理的q程有助于我们q一步理解UIU程与消息队列的关系Qؓ此我们需要简单地叙述一下MFCE序?生死因果"Q侯P《深入浅出MFC》）?br /> 使用VC++ 6.0的向导完成一个最单的单文架构MFC应用E序MFCThreadQ?br /> Q?Q?输入MFC EXE工程名MFCThreadQ?br /> Q?Q?选择单文档架构，不支持Document/Viewl构Q?br /> Q?Q?ActiveX?D container{其他选项都选择无?br /> 我们来分析这个工E。下面是产生的核心源代码Q?br /> MFCThread.h 文g class CMFCThreadApp : public CWinApp
{
public:
CMFCThreadApp();
// Overrides
// ClassWizard generated virtual function overrides
//{{AFX_VIRTUAL(CMFCThreadApp)
public:
virtual BOOL InitInstance();
//}}AFX_VIRTUAL
// Implementation
public:
//{{AFX_MSG(CMFCThreadApp)
afx_msg void OnAppAbout();
// NOTE - the ClassWizard will add and remove member functions here.
// DO NOT EDIT what you see in these blocks of generated code !
//}}AFX_MSG
DECLARE_MESSAGE_MAP()
}; |
MFCThread.cpp文g CMFCThreadApp theApp;
/////////////////////////////////////////////////////////////////////////////
// CMFCThreadApp initialization
BOOL CMFCThreadApp::InitInstance()
{
?br /> CMainFrame* pFrame = new CMainFrame;
m_pMainWnd = pFrame;
// create and load the frame with its resources
pFrame->LoadFrame(IDR_MAINFRAME,WS_OVERLAPPEDWINDOW | FWS_ADDTOTITLE, NULL,NULL);
// The one and only window has been initialized, so show and update it.
pFrame->ShowWindow(SW_SHOW);
pFrame->UpdateWindow();
return TRUE;
} |
MainFrm.h文g #include "ChildView.h"
class CMainFrame : public CFrameWnd
{
public:
CMainFrame();
protected:
DECLARE_DYNAMIC(CMainFrame)
// Attributes
public:
// Operations
public:
// Overrides
// ClassWizard generated virtual function overrides
//{{AFX_VIRTUAL(CMainFrame)
virtual BOOL PreCreateWindow(CREATESTRUCT& cs);
virtual BOOL OnCmdMsg(UINT nID, int nCode, void* pExtra, AFX_CMDHANDLERINFO* pHandlerInfo);
//}}AFX_VIRTUAL
// Implementation
public:
virtual ~CMainFrame();
#ifdef _DEBUG
virtual void AssertValid() const;
virtual void Dump(CDumpContext& dc) const;
#endif
CChildView m_wndView;
// Generated message map functions
protected:
//{{AFX_MSG(CMainFrame)
afx_msg void OnSetFocus(CWnd *pOldWnd);
// NOTE - the ClassWizard will add and remove member functions here.
// DO NOT EDIT what you see in these blocks of generated code!
//}}AFX_MSG
DECLARE_MESSAGE_MAP()
}; |
MainFrm.cpp文g IMPLEMENT_DYNAMIC(CMainFrame, CFrameWnd)
BEGIN_MESSAGE_MAP(CMainFrame, CFrameWnd)
//{{AFX_MSG_MAP(CMainFrame)
// NOTE - the ClassWizard will add and remove mapping macros here.
// DO NOT EDIT what you see in these blocks of generated code !
ON_WM_SETFOCUS()
//}}AFX_MSG_MAP
END_MESSAGE_MAP()
/////////////////////////////////////////////////////////////////////////////
// CMainFrame construction/destruction
CMainFrame::CMainFrame()
{
// TODO: add member initialization code here
}
CMainFrame::~CMainFrame()
{}
BOOL CMainFrame::PreCreateWindow(CREATESTRUCT& cs)
{
if( !CFrameWnd::PreCreateWindow(cs) )
return FALSE;
// TODO: Modify the Window class or styles here by modifying
// the CREATESTRUCT cs
cs.dwExStyle &= ~WS_EX_CLIENTEDGE;
cs.lpszClass = AfxRegisterWndClass(0);
return TRUE;
} |
ChildView.h文g // CChildView window
class CChildView : public CWnd
{
// Construction
public:
CChildView();
// Attributes
public:
// Operations
public:
// Overrides
// ClassWizard generated virtual function overrides
//{{AFX_VIRTUAL(CChildView)
protected:
virtual BOOL PreCreateWindow(CREATESTRUCT& cs);
//}}AFX_VIRTUAL
// Implementation
public:
virtual ~CChildView();
// Generated message map functions
protected:
//{{AFX_MSG(CChildView)
afx_msg void OnPaint();
//}}AFX_MSG
DECLARE_MESSAGE_MAP()
};
ChildView.cpp文g
// CChildView
CChildView::CChildView()
{}
CChildView::~CChildView()
{}
BEGIN_MESSAGE_MAP(CChildView,CWnd )
//{{AFX_MSG_MAP(CChildView)
ON_WM_PAINT()
//}}AFX_MSG_MAP
END_MESSAGE_MAP()
/////////////////////////////////////////////////////////////////////////////
// CChildView message handlers
BOOL CChildView::PreCreateWindow(CREATESTRUCT& cs)
{
if (!CWnd::PreCreateWindow(cs))
return FALSE;
cs.dwExStyle |= WS_EX_CLIENTEDGE;
cs.style &= ~WS_BORDER;
cs.lpszClass = AfxRegisterWndClass(CS_HREDRAW|CS_VREDRAW|CS_DBLCLKS,::LoadCursor(NULL, IDC_ARROW),
HBRUSH(COLOR_WINDOW+1),NULL);
return TRUE;
}
void CChildView::OnPaint()
{
CPaintDC dc(this); // device context for painting
// TODO: Add your message handler code here
// Do not call CWnd::OnPaint() for painting messages
} |
文gMFCThread.h和MFCThread.cpp定义和实现的cCMFCThreadAppl承自CWinAppc，而CWinAppcdl承
自CWinThreadc（CWinThreadcdl承自CCmdTargetc）Q所以CMFCThread本质上是一个MFCU程c，下图l出了相
关的cdơ结构： 我们提取CWinAppcd型的一部分Q?br /> class CWinApp : public CWinThread
{
DECLARE_DYNAMIC(CWinApp)
public:
// Constructor
CWinApp(LPCTSTR lpszAppName = NULL);// default app name
// Attributes
// Startup args (do not change)
HINSTANCE m_hInstance;
HINSTANCE m_hPrevInstance;
LPTSTR m_lpCmdLine;
int m_nCmdShow;
// Running args (can be changed in InitInstance)
LPCTSTR m_pszAppName; // human readable name
LPCTSTR m_pszExeName; // executable name (no spaces)
LPCTSTR m_pszHelpFilePath; // default based on module path
LPCTSTR m_pszProfileName; // default based on app name
// Overridables
virtual BOOL InitApplication();
virtual BOOL InitInstance();
virtual int ExitInstance(); // return app exit code
virtual int Run();
virtual BOOL OnIdle(LONG lCount); // return TRUE if more idle processing
virtual LRESULT ProcessWndProcException(CException* e,const MSG* pMsg);
public:
virtual ~CWinApp();
protected:
DECLARE_MESSAGE_MAP()
}; |
SDKE序的WinMain 所完成的工作现在由CWinApp 的三个函数完成： virtual BOOL InitApplication();
virtual BOOL InitInstance();
virtual int Run(); |
"CMFCThreadApp theApp;"语句定义的全局变量theApp是整个程式的application objectQ每一个MFC
应用E序都有一个。当我们执行MFCThreadE序的时候，q个全局变量被构造。theApp
配置完成后，WinMain开始执行。但是程序中q没有WinMain的代码，它在哪里呢？原来MFC早已准备好ƈ由Linker直接加到应用E序代码?
的，其原型ؓQ存在于VC++6.0安装目录下提供的APPMODUL.CPP文g中）Q?br /> extern "C" int WINAPI
_tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPTSTR lpCmdLine, int nCmdShow)
{
// call shared/exported WinMain
return AfxWinMain(hInstance, hPrevInstance, lpCmdLine, nCmdShow);
} |
其中调用的AfxWinMain如下Q存在于VC++6.0安装目录下提供的WINMAIN.CPP文g中）Q?br /> int AFXAPI AfxWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPTSTR lpCmdLine, int nCmdShow)
{
ASSERT(hPrevInstance == NULL);
int nReturnCode = -1;
CWinThread* pThread = AfxGetThread();
CWinApp* pApp = AfxGetApp();
// AFX internal initialization
if (!AfxWinInit(hInstance, hPrevInstance, lpCmdLine, nCmdShow))
goto InitFailure;
// App global initializations (rare)
if (pApp != NULL && !pApp->InitApplication())
goto InitFailure;
// Perform specific initializations
if (!pThread->InitInstance())
{
if (pThread->m_pMainWnd != NULL)
{
TRACE0("Warning: Destroying non-NULL m_pMainWnd\n");
pThread->m_pMainWnd->DestroyWindow();
}
nReturnCode = pThread->ExitInstance();
goto InitFailure;
}
nReturnCode = pThread->Run();
InitFailure:
#ifdef _DEBUG
// Check for missing AfxLockTempMap calls
if (AfxGetModuleThreadState()->m_nTempMapLock != 0)
{
TRACE1("Warning: Temp map lock count non-zero (%ld).\n",
AfxGetModuleThreadState()->m_nTempMapLock);
}
AfxLockTempMaps();
AfxUnlockTempMaps(-1);
#endif
AfxWinTerm();
return nReturnCode;
} |
我们提取dQ实际上Q这个函数做的事情主要是Q?br /> CWinThread* pThread = AfxGetThread();
CWinApp* pApp = AfxGetApp();
AfxWinInit(hInstance, hPrevInstance, lpCmdLine, nCmdShow)
pApp->InitApplication()
pThread->InitInstance()
pThread->Run(); |
其中QInitApplication
是注册窗口类别的场所QInitInstance是生窗口ƈ昄H口的场所QRun是提取ƈ分派消息的场所。这PMFC同WIN32
SDKE序对应h了。CWinThread::Run是程序生命的"zL源头"Q侯P《深入浅出MFC》，函数存在于VC++
6.0安装目录下提供的THRDCORE.CPP文g中）Q?br /> // main running routine until thread exits
int CWinThread::Run()
{
ASSERT_VALID(this);
// for tracking the idle time state
BOOL bIdle = TRUE;
LONG lIdleCount = 0;
// acquire and dispatch messages until a WM_QUIT message is received.
for (;;)
{
// phase1: check to see if we can do idle work
while (bIdle && !::PeekMessage(&m_msgCur, NULL, NULL, NULL, PM_NOREMOVE))
{
// call OnIdle while in bIdle state
if (!OnIdle(lIdleCount++))
bIdle = FALSE; // assume "no idle" state
}
// phase2: pump messages while available
do
{
// pump message, but quit on WM_QUIT
if (!PumpMessage())
return ExitInstance();
// reset "no idle" state after pumping "normal" message
if (IsIdleMessage(&m_msgCur))
{
bIdle = TRUE;
lIdleCount = 0;
}
} while (::PeekMessage(&m_msgCur, NULL, NULL, NULL, PM_NOREMOVE));
}
ASSERT(FALSE); // not reachable
} |
其中的PumpMessage函数又对应于Q?br /> /////////////////////////////////////////////////////////////////////////////
// CWinThread implementation helpers
BOOL CWinThread::PumpMessage()
{
ASSERT_VALID(this);
if (!::GetMessage(&m_msgCur, NULL, NULL, NULL))
{
return FALSE;
}
// process this message
if(m_msgCur.message != WM_KICKIDLE && !PreTranslateMessage(&m_msgCur))
{
::TranslateMessage(&m_msgCur);
::DispatchMessage(&m_msgCur);
}
return TRUE;
} |
因此Q忽略IDLE状态，整个RUN的执行提取主q就是： do {
::GetMessage(&msg,...);
PreTranslateMessage{&msg);
::TranslateMessage(&msg);
::DispatchMessage(&msg);
...
} while (::PeekMessage(...)); |
由此Q我们徏立了MFC消息获取和派生机制与WIN32 SDKE序之间的对应关pR下面l分析MFC消息?l行"q程?br />
在MFC中，只要是CWnd 衍生cdQ就可以拦下MWindows消息。与H口无关的MFCcdQ例如CDocument
和CWinAppQ如果也惛_理消息，必须衍生自CCmdTargetQƈ且只可能收到WM_COMMAND消息。所有能q行MESSAGE_MAP的类
都承自CCmdTargetQ如Q?br /> MFC中MESSAGE_MAP的定义依赖于以下三个宏： DECLARE_MESSAGE_MAP()
BEGIN_MESSAGE_MAP(
theClass, //Specifies the name of the class whose message map this is
baseClass //Specifies the name of the base class of theClass
)
END_MESSAGE_MAP() |
我们E序中涉及到的有QMFCThread.h、MainFrm.h、ChildView.h文g DECLARE_MESSAGE_MAP()
MFCThread.cpp文g
BEGIN_MESSAGE_MAP(CMFCThreadApp, CWinApp)
//{{AFX_MSG_MAP(CMFCThreadApp)
ON_COMMAND(ID_APP_ABOUT, OnAppAbout)
// NOTE - the ClassWizard will add and remove mapping macros here.
// DO NOT EDIT what you see in these blocks of generated code!
//}}AFX_MSG_MAP
END_MESSAGE_MAP()
MainFrm.cpp文g
BEGIN_MESSAGE_MAP(CMainFrame, CFrameWnd)
//{{AFX_MSG_MAP(CMainFrame)
// NOTE - the ClassWizard will add and remove mapping macros here.
// DO NOT EDIT what you see in these blocks of generated code !
ON_WM_SETFOCUS()
//}}AFX_MSG_MAP
END_MESSAGE_MAP()
ChildView.cpp文g
BEGIN_MESSAGE_MAP(CChildView,CWnd )
//{{AFX_MSG_MAP(CChildView)
ON_WM_PAINT()
//}}AFX_MSG_MAP
END_MESSAGE_MAP() |
p些宏QMFC建立了一个消息映表Q消息流动网Q，按照消息动|匹配对应的消息处理函数Q完成整个消息的"l行"?br /> 看到q里怿你有q样的疑问：E序定义了CWinAppcȝtheApp全局变量Q可是从来没有调用AfxBeginThread或theApp.CreateThread启动U程呀QtheApp对应的线E是怎么启动的？ {：MFC在这里用了很高明的一招。实际上Q程序开始运行，W一个线E是由操作系l（OSQ启动的Q在CWinApp的构造函数里QMFCtheApp"对应"向了q个U程Q具体的实现是这LQ?br /> CWinApp::CWinApp(LPCTSTR lpszAppName)
{
if (lpszAppName != NULL)
m_pszAppName = _tcsdup(lpszAppName);
else
m_pszAppName = NULL;
// initialize CWinThread state
AFX_MODULE_STATE *pModuleState = _AFX_CMDTARGET_GETSTATE();
AFX_MODULE_THREAD_STATE *pThreadState = pModuleState->m_thread;
ASSERT(AfxGetThread() == NULL);
pThreadState->m_pCurrentWinThread = this;
ASSERT(AfxGetThread() == this);
m_hThread = ::GetCurrentThread();
m_nThreadID = ::GetCurrentThreadId();
// initialize CWinApp state
ASSERT(afxCurrentWinApp == NULL); // only one CWinApp object please
pModuleState->m_pCurrentWinApp = this;
ASSERT(AfxGetApp() == this);
// in non-running state until WinMain
m_hInstance = NULL;
m_pszHelpFilePath = NULL;
m_pszProfileName = NULL;
m_pszRegistryKey = NULL;
m_pszExeName = NULL;
m_pRecentFileList = NULL;
m_pDocManager = NULL;
m_atomApp = m_atomSystemTopic = NULL; //微Y懒鬼Q或者他认ؓ
//q样q等含义更明？
m_lpCmdLine = NULL;
m_pCmdInfo = NULL;
// initialize wait cursor state
m_nWaitCursorCount = 0;
m_hcurWaitCursorRestore = NULL;
// initialize current printer state
m_hDevMode = NULL;
m_hDevNames = NULL;
m_nNumPreviewPages = 0; // not specified (defaults to 1)
// initialize DAO state
m_lpfnDaoTerm = NULL; // will be set if AfxDaoInit called
// other initialization
m_bHelpMode = FALSE;
m_nSafetyPoolSize = 512; // default size
} |
很显ӞtheApp成员变量都被赋予OS启动的这个当前线E相关的|如代码： m_hThread = ::GetCurrentThread();//theApp的线E句柄等于当前线E句?
m_nThreadID = ::GetCurrentThreadId();//theApp的线EID{于当前U程ID |
所以CWinAppcd乎只是ؓMFCE序的第一个线E量w定制的Q它不需要也不能被AfxBeginThread?
theApp.CreateThread"再次"启动。这是CWinAppcdtheApp全局变量的内涵！如果你要再增加一个UIU程Q不要承类
CWinAppQ而应l承cCWinThread。而参考第1节，׃我们一般以ȝE（在MFCE序里实际上是OS启动的第一个线E）处理所有窗口的
消息Q所以我们几乎没有再启动UIU程的需求！
|
