28-进程间通信：匿名管道

进程间通信：匿名管道

匿名管道是一个没有命名的单向管道，本质上就是一个共享的内存区域。通常用来在父进程和子进程之间通信。

注：只能实现本地两个进程之间的通信。不能实现网络通信。

1.创建匿名管道函数

CreatePipe(
_Out_ PHANDLE hReadPipe,	 //该变量接收管道的读取句柄
_Out_ PHANDLE hWritePipe,	// 该变量接收管道的写句柄
_In_opt_ LPSECURITY_ATTRIBUTES lpPipeAttributes,//NULL
_In_ DWORD nSize 			//管道缓冲区的大小 0 :默认缓冲区大小
);

2.父进程程序

使用时修改子进程名称，其余一致

HANDLE hReadPipe;						//创建在该进程下，能够读取和写入管道的全局句柄
HANDLE hWritePipe;
void CChildView::OnPipeCreate()			//对应创建子进程的按钮
{
    // TODO: 在此添加命令处理程序代码
    //创建匿名管道
    SECURITY_ATTRIBUTES sa;
    sa.bInheritHandle = TRUE;
    sa.lpSecurityDescriptor = NULL;
    sa.nLength = sizeof(SECURITY_ATTRIBUTES);
    if (!CreatePipe(&hReadPipe, &hWritePipe, &sa, 0))
    {
        MessageBox(_T("匿名管道创建失败"));
        return;
    }
    //创建子进程
    STARTUPINFO strStartupInfo; //用来指定新进程窗口如何显示
    memset(&strStartupInfo, 0, sizeof(strStartupInfo));
    strStartupInfo.cb = sizeof(strStartupInfo);
    strStartupInfo.dwFlags = STARTF_USESTDHANDLES;
    strStartupInfo.hStdInput = hReadPipe;
    strStartupInfo.hStdOutput = hWritePipe;
    strStartupInfo.hStdError = GetStdHandle(STD_ERROR_HANDLE);
    PROCESS_INFORMATION szProcessInformation;
    memset(&szProcessInformation, 0, sizeof(szProcessInformation));
    //准备工作完成，开始创建
    int iRet = CreateProcess(
        _T("MailSlotClient.exe"),		//子进程名称
        NULL,
        NULL,
        NULL,
        TRUE,
        0,
        NULL,
        NULL,
        &strStartupInfo,
        &szProcessInformation
    );
    if (iRet)
    {
        //创建成功
        CloseHandle(szProcessInformation.hProcess);
        CloseHandle(szProcessInformation.hThread);
        szProcessInformation.dwProcessId = 0;
        szProcessInformation.dwThreadId = 0;
        szProcessInformation.hThread = NULL;
        szProcessInformation.hProcess = NULL;
    }
    else
    {
        CloseHandle(hReadPipe);
        CloseHandle(hWritePipe);
        hReadPipe = NULL;
        hWritePipe = NULL;
        MessageBox(_T("创建子进程失败"));
        return;
    }
}
void CChildView::OnPipeRead()			//对应接收按钮
{
    char szBuf[100] = { 0 };
    DWORD dwRead;
    TRACE("Begin ReadFile");
    if (!ReadFile(hReadPipe, szBuf, 100, &dwRead, NULL))
    {
        MessageBox(_T("读取数据失败"));
        return;
    }
    TRACE("End PipeReadFile");
	MessageBox((CStringW)szBuf);
}
void CChildView::OnPipeWrite()			//对应发送按钮
{
    //写入数据
    char szBuf[] = "Bingo hen shuai";
    DWORD dwWrite;
    if (!WriteFile(hWritePipe, szBuf, strlen(szBuf) + 1, &dwWrite, NULL))
    {
        MessageBox(_T("写入数据失败"));
        return;
	}
}

3.子进程程序

该进程由于是父进程打开的，因此能使用GetStdHandle(STD_INPUT_HANDLE)来共享父进程传递来的句柄

void CChildView::OnCliPipeRead()
{
    HANDLE hReadCliPipe =GetStdHandle(STD_INPUT_HANDLE);
    char szBuf[100] = { 0 };
    DWORD dwRead;
    TRACE("Begin ReadFile"); //查找所有引用shift + alt + F
    if (!ReadFile(hReadCliPipe, szBuf, 100, &dwRead, NULL))
    {
        MessageBox(_T("读取数据失败"));
        return;
    }
    TRACE("End PipeReadFile");
    MessageBox((CStringW)szBuf);
}
void CChildView::OnCliPipeWrite()
{
    HANDLE hWriteCliPipe = GetStdHandle(STD_OUTPUT_HANDLE);
    char szBuf[] = "Bingo Bingo";
    DWORD dwWrite;
    if (!WriteFile(hWriteCliPipe, szBuf, strlen(szBuf) + 1, &dwWrite, NULL))
    {
        MessageBox(_T("写入数据失败"));
        CloseHandle(hWriteCliPipe);
        return;
    }
    CloseHandle(hWriteCliPipe);
}

发布于 2022-11-08