overlapped-io

I have a problem with ReadFile and overlapped. first I use ReadFile with overlapped with 0 ZeroMemory(&overlapped ,sizeof(OVERLAPPED)); hDevice = CreateFileW(zwpath, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL); if(hDevice != INVALID_HANDLE_VALUE){ ret = ReadFile(hDevice, buff, 1024, &numerobyte, &overlapped); } with a for(), I can see the bytes using a printf() for (int n=0; n<sizeof(buff); n++) { printf("0x%02X ", buff[n]); } and now I have one variant with a large number crbig = 322122547 d1 =

I need to add timers support in an application based on I/O Completion Ports (IOCP). I would like to avoid the use of a specific thread to manage timers. On Linux, you can create a timer that delivers expiration notifications via a file descriptor (see timerfd.h man), so it's great to use it for example with epoll if your application is based on epoll. On Windows, you can use "waitable timers" with an asynchronous procedure call (ACP) (see http://msdn.microsoft.com/en-us/library/ms686898(v=VS.85).aspx ) If you are interested, kqueue (BSD, Mac OS) supports timers by default (see EVFILT_TIMER).

I need to find a way to be notified when a System.IO.Pipe.NamedPipeServerStream opened in asynchronous mode has more data available for reading on it- a WaitHandle would be ideal. I cannot simply use BeginRead() to obtain such a handle because it's possible that i might be signaled by another thread which wants to write to the pipe- so I have to release the lock on the pipe and wait for the write to be complete, and NamedPipeServerStream doesnt have a CancelAsync method. I also tried calling BeginRead(), then calling the win32 function CancelIO on the pipe if the thread gets signaled, but I

For some reason, my callback isn't receiving the address of the correct OVERLAPPED structure after a call to ReadFileEx . What can cause this? Update -- example: #include <stdio.h> #include <Windows.h> void __stdcall completion_routine( unsigned long dwErrorCode, unsigned long dwNumberOfBytesTransfered, OVERLAPPED *lpOverlapped) { printf("Overlapped = %p\n", lpOverlapped); } int _tmain(int argc, LPTSTR argv[]) { HANDLE hvolume = CreateFile( _T("C:\\Windows\\Notepad.exe"), FILE_READ_DATA, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL, OPEN_EXISTING, 0, NULL); char tempbuf[512];

I'm attempting to use overlapped IO to read input from the console by opening CONIN$ with the FILE_FLAG_OVERLAPPED flag. However, ReadFile blocks when I use it, even with an OVERLAPPED parameter. I've read some posts reporting that this is a Windows 7 bug. I am using 7 so that could be possible. Here's the code I'm using: // 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

Consider an application that is CPU bound, but also has high-performance I/O requirements. I'm comparing Linux file I/O to Windows, and I can't see how epoll will help a Linux program at all. The kernel will tell me that the file descriptor is "ready for reading," but I still have to call blocking read() to get my data, and if I want to read megabytes, it's pretty clear that that will block. On Windows, I can create a file handle with OVERLAPPED set, and then use non-blocking I/O, and get notified when the I/O completes, and use the data from that completion function. I need to spend no