我试图通过使用 FILE_FLAG_OVERLAPPED 标志打开 CONIN$ 来使用重叠 IO 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。
我读过一些帖子报告这是一个 Windows 7 错误。我正在使用 7,所以这是可能的。
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;
}