GHC 10.0.0.20260917 · lts/ghc-10.0.x · 8fef28d · 2026-11-02
Modulefsnotify-0.4.4.0Haskell2010
This library does not currently report changes made to directories, only files within watched directories.
Minimal example:
{-# LANGUAGE OverloadedStrings #-} -- for FilePath literals
import System.FSNotify
import Control.Concurrent (threadDelay)
import Control.Monad (forever)
main =
withManager $ \mgr -> do
-- start a watching job (in the background)
watchDir
mgr -- manager
"." -- directory to watch
(const True) -- predicate
print -- action
-- sleep forever (until interrupted)
forever $ threadDelay 1000000A file event reported by a file watcher. Each event contains the canonical path for the file and a timestamp guaranteed to be after the event occurred (timestamps represent current time when FSEvents receives it from the OS and/or platform-specific Haskell modules).
AddedModifiedModifiedAttributesRemovedWatchedDirectoryRemovedNote: Linux-only
CloseWriteNote: Linux-only
UnknownNote: Linux-only
Eq EventIsDirectoryDefined in fsnotify-0.4.4.0 · System.FSNotify.TypesShow EventIsDirectoryDefined in fsnotify-0.4.4.0 · System.FSNotify.TypesAn action to be performed in response to an event.
A predicate used to determine whether to act on an event.
Watch manager. You need one in order to create watching jobs.
Perform an IO action with a WatchManager in place. Tear down the WatchManager after the action is complete.
Start a file watch manager. Directories can only be watched when they are managed by a started watch manager. When finished watching. you must release resources via stopManager. It is preferrable if possible to use withManager to handle this automatically.
Stop a file watch manager. Stopping a watch manager will immediately stop watching for files and free resources.
Default configuration
Uses OS watch mode (if possible) and single thread.
Watch configuration.
Watch mode to use.
Threading mode to use.
Called when a handler throws an exception.
Method of watching for changes.
WatchModePollwatchModePollInterval :: IntPolling interval in microseconds.
WatchModeOSUse OS-specific mechanisms to be notified of changes (inotify on Linux, FSEvents on OSX, etc.). Not currently available on e.g. *BSD and Wasm/WASI.
SingleThreadUse a single thread for the entire Manager. Event handler callbacks will run sequentially.
ThreadPerWatchUse a single thread for each watch (i.e. each call to watchDir, watchTree, etc.).
Callbacks within a watch will run sequentially but callbacks from different watches may be interleaved.
ThreadPerEventLaunch a separate thread for every event handler.
Like withManager, but configurable.
Like startManager, but configurable.
An action that cancels a watching/listening job.
Watch the immediate contents of a directory by committing an Action for each event. Watching the immediate contents of a directory will only report events associated with files within the specified directory, and not files within its subdirectories.
Watch the immediate contents of a directory by streaming events to a Chan. Watching the immediate contents of a directory will only report events associated with files within the specified directory, and not files within its subdirectories.
Watch all the contents of a directory by committing an Action for each event. Watching all the contents of a directory will report events associated with files within the specified directory and its subdirectories.
Watch all the contents of a directory by streaming events to a Chan. Watching all the contents of a directory will report events associated with files within the specified directory and its subdirectories.