多線程中的臨界區(qū)

臨界區(qū)又叫關(guān)鍵代碼段.在多線程共享變量時(shí),用來安全讀寫共享變量.代碼如下:

CRITICAL_SECTION   g_csSync = {};//臨界區(qū)
INT   g_iData = 0;

DWORD  WINAPI  WriteThreadProc(LPVOID lpParameter)
{//寫線程
	while (1)
	{
		Sleep(30);
		__try
		{
			EnterCriticalSection(&g_csSync);
			g_iData++;
		}
		__finally
		{
			LeaveCriticalSection(&g_csSync);
		}
	}
	return 0;
}

DWORD WINAPI  ReadThreadProc(LPVOID lpParameter)
{//讀線程
	while (true)
	{
		Sleep(30);
		__try
		{
			EnterCriticalSection(&g_csSync);//進(jìn)入臨界區(qū)

			char str[20] = {};
			itoa(g_iData, str, 10);
			TRACE(str);
		}
		__finally
		{
			LeaveCriticalSection(&g_csSync);//離開臨界區(qū)
		}
	}
	return 0;
}
void CtestThreadDlg::OnBnClickedButton16()
{
	InitializeCriticalSectionAndSpinCount(&g_csSync, 0x4000);//初始化臨界區(qū)

	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);//刪除臨界區(qū)
}