Author of the article: oury during the time of multi-threaded programming, we often use AfxBeginThread function to start a thread to use this function is very simple, which is defined as follows CWinThread * AfxBeginThread (AFX_THREADPROC pfnThreadProc, // thread function address LPVOID pParam, // thread parameters int nPriority = THREAD_PRIORITY_NORMAL, // thread priority UINT nStackSize = 0, // thread stack size, default is 1M DWORD dwCreateFlags = 0, // LPSECURITY_ATTRIBUTES lpSecurityAttrs = NULL); CWinThread * AfxBeginThread (CRuntimeClass * pThreadClass, int nPriority = THREAD_PRIORITY_NORMAL, UINT nStackSize = 0, DWORD dwCreateFlags = 0, LPSECURITY_ATTRIBUTES lpSecurityAttrs = NULL); parameters: pfnThreadProc: address of the thread function, this parameter is not set to NULL, the thread function must be defined as a static member function global function or class For example: uint mythreadfunc (lpvoid lparam) or class a {public: static uint __stdcall mythreadfunc (lpvoid lparam);} To define a static member function that is classified, it is because the static member functions of the class are not a class object, so You don't have to deliver an extra THIS pointer when calling the function. PthreadClass: Points to Runtime_Classpparam from the subclass of CwinThread derived: Parameters to pass to the thread function NPRIORITY: The priority of the thread to be started, the default priority is thread_priority_normal ( Ordinary priority), please refer to the Platform SDK SetThreadPriority function description NSTACKSIZE: The stack size of the new thread, if set to 0, use the default size, in the application, the default stack size of the thread in the application 1MDWCREATEFLAGS: Thread Creation Sign This parameter can be specified as the following flag CREATE_SUSPENDED: start the thread in a hang, if you want to initialize some of the member variables in some CwinThread classes before the thread startup, such as: m_bautdelete or member variables in your derived class, when the initialization is completed You can use the CWINTHREAD class RESUMETHREAD member function to restore the thread run if the flag is set to 0, then start thread LPSecurityATTRS: pointing to the pointer to the security descriptor, if you use the default security level As long as this parameter is set to null Yes! The above is a brief description of the AFXBEGINTHREAD function. We are in use. Generally, as long as the first two parameters are specified, other parameters can be used by default. Well, indeed, it is very simple, as long as this function is Come created a thread. But have you ever thought that the AFXBEGINTHREAD function is how to start thread? How is its internal implementation? Let's take a look at the internal implementation of the AfxBeginThread function // Start Worker thread CWinThread * AFXAPI AfxBeginThread (AFX_THREADPROC pfnThreadProc, LPVOID pParam, int nPriority, UINT nStackSize, DWORD dwCreateFlags, LPSECURITY_ATTRIBUTES lpSecurityAttrs) {# ifndef _MT pfnThreadProc; pParam; nPriority; nStackSize; dwCreateFlags; lpSecurityAttrs;
return NULL; #else ASSERT (! pfnThreadProc = NULL); CWinThread * pThread = DEBUG_NEW CWinThread (pfnThreadProc, pParam); ASSERT_VALID (pThread); if | {pThread- (pThread-> CreateThread (dwCreateFlags CREATE_SUSPENDED, nStackSize, lpSecurityAttrs)!) > Delete (); return null;} verify (pthread-> setthreadpriority (npriority)); if (! (Dwcreateflags & create_suspend)) Verify (pthread-> resumethread ()! = (Dword) -1); return pthread; # endif // _ MT)} // start the UI thread CWinThread * AFXAPI AfxBeginThread (CRuntimeClass * pThreadClass, int nPriority, UINT nStackSize, DWORD dwCreateFlags, LPSECURITY_ATTRIBUTES lpSecurityAttrs) {# ifndef _MT pThreadClass;! nPriority; nStackSize; dwCreateFlags; lpSecurityAttrs; return NULL; #else ASSERT (pThreadClass = NULL!); ASSERT (pThreadClass-> IsDerivedFrom (RUNTIME_CLASS (CWinThread))); CWinThread * pThread = (CWinThread *) pThreadClass-> CreateObject (); if (pThread == NULL) AfxT hrowMemoryException (); ASSERT_VALID (pThread); pThread-> m_pThreadParams = NULL; if | {pThread-> Delete (); return NULL;} (pThread-> CreateThread (dwCreateFlags CREATE_SUSPENDED, nStackSize, lpSecurityAttrs)!) VERIFY (pThread-> SetthreadPriority (NPRIORITY)); if (! (Dwcreateflags & create_suspend)) Verify (pthread-> resumethread ()! = (Dword) -1); return pthread; #ENDIF / /! _ MT} It can be seen from the code above doing things AfxBeginThread following main points: 1 configure a new CWinThread objects (worker thread) code in the heap as:. CWinThread * pThread = DEBUG_NEW CWinThread (pfnThreadProc, pParam); call CRuntimeClass structure CreateObject function to create CWinThread Object CWINTHREAD * pthread =
