kqueue

If you use kqueue(), should you set O_NONBLOCK on your file descriptors? In other words, does kqueue() guarantee that the next I/O operation on a ready file descriptor will not block, regardless of whether O_NONBLOCK is set? If you use kqueue(), should you set O_NONBLOCK on your file descriptors? Nope. In other words, does kqueue() guarantee that the next I/O operation on a ready file descriptor will not block, regardless of whether O_NONBLOCK is set? Yep. You do not need to. However, I generally do as a sanity check. This makes operations like read() return -1 and set errno to EWOULDBLOCK. I

I'm working on an application that uses fifos for IPC and uses an event-notification API (such as epoll or kqueue) to monitor the fifos for data to be read. The application expects that if the writer for a fifo terminates that the reader will receive an event via the event notification API, allowing the reader to notice that the writer terminated. I'm currently porting this application to macos and I'm running into some odd behavior with kqueue. I've been able to create a reproducer of this behavior: #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <fcntl.h> #include <string

I am reading Redis recently. Redis implements a simple event-driven library based on I/O multiplexing. Redis says it would choose the best multiplexing supported by the system, and gives the following code: /* Include the best multiplexing layer supported by this system. * The following should be ordered by performances, descending. */ #ifdef HAVE_EVPORT #include "ae_evport.c" #else #ifdef HAVE_EPOLL #include "ae_epoll.c" #else #ifdef HAVE_KQUEUE #include "ae_kqueue.c" #else #include "ae_select.c" #endif #endif #endif I wanna know whether they have fundamental performance differences? If so,

I want my code to be notified when any file under (either directly or indirectly) a given directory is modified. By "modified", I mean I want my code to be notified whenever a file's contents are altered, it's renamed, or it's deleted; or if a new file is added. For my application, there can be thousands of files. I looked as FSEvents, but its Technology Overview says, in part: The important point to take away is that the granularity of notifications is at a directory level. It tells you only that something in the directory has changed, but does not tell you what changed. It also says: The

OK: I'm implementing File Sharing in an iPhone OS app, and of course this means filesystem monitoring. Yay! Basically, the OS copies and/or deletes from and to a directory I can access when the user manipulates files into my app's section in iTunes. Thus, I need to monitor the directory for changes presumably via an efficient mechanism like a kqueue() . How do I implement this so that I know that the files have finished copying? I was thinking along the lines of: Monitor with kqueue() . At event, start (or reset existing) timeout. When timeout elapses, do work. but is there a better way of