临界区又叫关键代码段.在多线程共享变量时,用来安全读写共享变量.代码如下:

CRITICAL_SECTION   g_csSync = {};//临界区INT   g_iData = 0;DWORD  WINAPI  WriteThreadProc(LPVOID lpParameter){//写线程	while (1)	{		Sleep(30);		__try		{			EnterCriticalSection(&g_csSync);			g_iData++;		}		__finally		{			LeaveCriticalSection(&g_csSync);		}	}	return 0;}DWORD WINAPI  ReadThreadProc(LPVOID lpParameter){//读线程	while (true)	{		Sleep(30);		__try		{			EnterCriticalSection(&g_csSync);//进入临界区			char str[20] = {};			itoa(g_iData, str, 10);			TRACE(str);		}		__finally		{			LeaveCriticalSection(&g_csSync);//离开临界区		}	}	return 0;}void CtestThreadDlg::OnBnClickedButton16(){	InitializeCriticalSectionAndSpinCount(&g_csSync, 0x4000);//初始化临界区	DWORD  ThreadID = 0;	HANDLE  hThread[2] = {};	hThread[0] = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)WriteThreadProc, 	                     NULL, CREATE_SUSPENDED, &ThreadID);	hThread[1] = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)ReadThreadProc, 	                     NULL, CREATE_SUSPENDED, &ThreadID);	ResumeThread(hThread[0]);	ResumeThread(hThread[1]);	WaitForMultipleObjects(2, hThread, TRUE, INFINITE);	CloseHandle(hThread[0]);	CloseHandle(hThread[1]);	DeleteCriticalSection(&g_csSync);//删除临界区}