Question

我正在尝试使用重叠IO通过使用FILE_FLAG_OVERLAPPED标志打开CONIN $来从控制台读取输入。但是，当我使用它时，ReadFile会阻塞，即使使用OVERLAPPED参数也是如此。

我已经阅读了一些报道这是Windows 7错误的帖子。我正在使用7这样才有可能。

这是我正在使用的代码：

// Create a console window
AllocConsole();
AttachConsole(GetProcessId(GetModuleHandle(NULL)));

HANDLE overlappedConsoleIn = CreateFile(L"CONIN$",
                              GENERIC_READ,
                              FILE_SHARE_READ,
                              NULL,
                              OPEN_EXISTING,
                              FILE_FLAG_OVERLAPPED | FILE_FLAG_NO_BUFFERING,
                              NULL);

// Set up the console to work with stdio
FILE *consoleOut = _fdopen(_open_osfhandle((long)GetStdHandle(STD_OUTPUT_HANDLE), _O_TEXT), "w");
FILE *consoleIn = _fdopen(_open_osfhandle((long)overlappedConsoleIn, _O_TEXT), "r");

*stdout = *consoleOut;
*stdin = *consoleIn;

setvbuf(consoleOut, NULL, _IONBF, 0);
setvbuf(consoleIn, NULL, _IONBF, 0);

std::ios::sync_with_stdio();

// Create a completion event
HANDLE inputEvent = CreateEvent(NULL, true, false, NULL);

BYTE inputBuffer[128];

OVERLAPPED overlappedData;
overlappedData.Offset = 0;
overlappedData.OffsetHigh = 0;
overlappedData.hEvent = inputEvent;

DWORD numBytesRead = 0;

// Asynchronously read from console
ReadFile(overlappedConsoleIn, inputBuffer, 128, &numBytesRead, &overlappedData);

while(true)
{
    if(WaitForSingleObject(inputEvent, 0) == WAIT_OBJECT_0)
    {
        std::cout << "input has been received" << std::endl;
    }
    std::cout << "doing something" << std::endl;
}

Answer 1

当您打开CONIN$或CONOUT$时，将忽略参数dwFlagsAndAttributes（在CreateFile功能的文档中有关于如何打开控制台的完整说明）。如果您想异步读取控制台，可以将CreateFile返回的句柄直接传递给WaitForSingleObject函数，如果有任何Console事件处于挂起状态，则会通过函数{{3}发出此句柄的信号。你读过待处理的事件吗？ ReadConsoleInput是如何在Windows中使用控制台的完整文档。

使用重叠IO进行控制台输入？

1 个答案: