A V module for asynchronously watching for file changes in a directory. The module is essentially a wrapper for septag/dmon. It works for Windows, macOS and Linux.

Currently vmon offers a few additional features over the code in dmon.

• Automatic shared access to the user data in the callback thread (via sync.Mutex)
• Automatic init/free of memory resources on clean program exits

v install https://github.com/larpon/vmon

For example usage see examples/watch_and_wait

v run ~/.vmodules/vmon/examples/watch_and_wait

To watch a directory asynchronously for file changes simply do:

import os
import vmon

fn watch_callback(watch_id vmon.WatchID, action vmon.Action, root_path string, file_path string, old_file_path string, user_data voidptr) {
	// ... do stuff here
}

fn main() {
	vmon.watch(os.home_dir(), watch_callback, 0, voidptr(0)) or { panic(err) }
	// ... do stuff here, wait or block the main thread, e.g.:
	time.sleep(10 * time.second)
}

Since the file watching is running in it's own thread remember to block your main thread while watching for changes, otherwise the app will exit immediately.

Please note that septag/dmon is licensed under BSD 2-clause while the V wrapper code is licensed under MIT.

Please also note that your user need correct file permission access to the directories you're trying to watch. So watching a place like /tmp on Unix isn't always possible since this is usually owned by root. However, you're usually allowed to make subdirectories in /tmp which can be watched.

Also please note that currently you won't receive events from changes to directories in the watched path since this is not supported in the C project we rely on.