sam_sp_44_sem.cpp

专题讲座四：内容包括为什么需要多进程或线程 、进程控制、线程控制、进程或线程间同步、进程间通信等。附例程。

// sam_sp_44_sem.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "sam_sp_44_sem.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// The one and only application object

CWinApp theApp;

DWORD threadA(void* pD)
{
	int iID=(int)pD;
	//在内部重新打开
	HANDLE hCounterIn=OpenSemaphore(SEMAPHORE_ALL_ACCESS,FALSE,"sam sp 44");

	for(int i=0;i<3;i++)
	{
		printf("%d wait for object\n",iID);
		WaitForSingleObject(hCounterIn,INFINITE);
		printf("\t\tthread %d : do database access call\n",iID);
		Sleep(100);
		printf("\t\tthread %d : do database access call end\n",iID);
		ReleaseSemaphore(hCounterIn,1,NULL);
	}
	CloseHandle(hCounterIn);
	return 0;
}

using namespace std;

int _tmain(int argc, TCHAR* argv[], TCHAR* envp[])
{
	int nRetCode = 0;

	// initialize MFC and print and error on failure
	if (!AfxWinInit(::GetModuleHandle(NULL), NULL, ::GetCommandLine(), 0))
	{
		// TODO: change error code to suit your needs
		cerr << _T("Fatal Error: MFC initialization failed") << endl;
		nRetCode = 1;
	}
	else
	{
		// TODO: code your application's behavior here.
		//创建信号灯
		HANDLE hCounter=NULL;
		if( (hCounter=OpenSemaphore(SEMAPHORE_ALL_ACCESS,FALSE,"sam sp 44"))==NULL)
		{
			//如果没有其他进程创建这个信号灯，则重新创建
			hCounter = CreateSemaphore(NULL,2,2,"sam sp 44");
		}

		//创建线程
		HANDLE hThread[3];
		CWinThread* pT1=AfxBeginThread((AFX_THREADPROC)threadA,(void*)1);
		CWinThread* pT2=AfxBeginThread((AFX_THREADPROC)threadA,(void*)2);
		CWinThread* pT3=AfxBeginThread((AFX_THREADPROC)threadA,(void*)3);
		hThread[0]=pT1->m_hThread;
		hThread[1]=pT2->m_hThread;
		hThread[2]=pT3->m_hThread;
		//等待线程结束
		WaitForMultipleObjects(3,hThread,TRUE,INFINITE);

		//关闭句柄
		CloseHandle(hCounter);	
	}

	return nRetCode;
}