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
This is a FIFO queue in GCD: dispatch_queue_t serialQueue = dispatch_queue_create(“com.blah.queue”, DISPATCH_QUEUE_SERIAL); … dispatch_async(serialQueue, ^{ //block1 }); dispatch_async(serialQueue, ^{ //block2 });
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
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
Neither. Your collection has a fixed size and std::array is sufficient. The data structure you implement is called a ring buffer. To implement it you create an array and keep track of the offset of the current first element. When you add an element that would push an item out of the buffer – i.e. … Read more
FIFO means first-in-first-out. The data structure you’re looking for is called a Queue.
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
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
You’re looking for any class that implements the Queue interface, excluding PriorityQueue and PriorityBlockingQueue, which do not use a FIFO algorithm. Probably a LinkedList using add (adds one to the end) and removeFirst (removes one from the front and returns it) is the easiest one to use. For example, here’s a program that uses a … 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