You could open() your pipe O_RDONLY | O_NONBLOCK, and if you want the C stream, you can get it with fdopen(). However, there might be a problem with the select() – AFAIK, a pipe fd open for reading that has no writer is always prepared for reading, and read() returns 0, so the select() would … Read more
If you want to keep the file as a persistent store of your data to prevent a loss of stream in case of a system crash or one of the members in your network of running processes dies, you can still continue on writing to a file and reading from it. If you do not … Read more
That’s just the way it’s defined. From the Open Group page for the open() function O_NONBLOCK When opening a FIFO with O_RDONLY or O_WRONLY set: If O_NONBLOCK is set: An open() for reading only will return without delay. An open() for writing only will return an error if no process currently has the file open … Read more
In fact, if what you want is a basic and easy to use fifo queue, slice provides all you need. queue := make([]int, 0) // Push to the queue queue = append(queue, 1) // Top (just get next element, don’t remove it) x = queue[0] // Discard top element queue = queue[1:] // Is empty … Read more
The O in FIFO means “out”. Once your data is “out”, it’s gone. 🙂 So naturally if another process comes along and someone else has already issued a read, the data isn’t going to be there twice. To accomplish what you suggest you should look into Unix domain sockets. Manpage here. You can write a … Read more
I would write a wrapper class that on Enqueue would check the Count and then Dequeue when the count exceeds the limit. public class FixedSizedQueue<T> { readonly ConcurrentQueue<T> q = new ConcurrentQueue<T>(); private object lockObject = new object(); public int Limit { get; set; } public void Enqueue(T obj) { q.Enqueue(obj); lock (lockObject) { T … Read more
os.mkfifo() will fail with exception OSError: [Errno 17] File exists if the file already exists, so there is no security issue here. The security issue with using tempfile.mktemp() is the race condition where it is possible for an attacker to create a file with the same name before you open it yourself, but since os.mkfifo() … Read more
Inspired by your question I’ve written a simple program that will let you do this: $ myprogram 2>&1 | ftee /tmp/mylog It behaves similarly to tee but clones the stdin to stdout and to a named pipe (a requirement for now) without blocking. This means that if you want to log this way it may … Read more
Since there are a myriad of answers, you might be confused, but to summarize: Use a std::queue. The reason for this is simple: it is a FIFO structure. You want FIFO, you use a std::queue. It makes your intent clear to anybody else, and even yourself. A std::list or std::deque does not. A list can … Read more
You cannot create a named pipe by calling CreateFile(..). Have a look at the pipe examples of the MSDN. Since these examples are quite complex I’ve quickly written a VERY simple named pipe server and client. int main(void) { HANDLE hPipe; char buffer[1024]; DWORD dwRead; hPipe = CreateNamedPipe(TEXT(“\\\\.\\pipe\\Pipe”), PIPE_ACCESS_DUPLEX, PIPE_TYPE_BYTE | PIPE_READMODE_BYTE | PIPE_WAIT, // … Read more