I looked at some of the apis for file watching, allot of 1000's of lines of oo; its badly designed c apis blah blah blah; it belongs in the std. Id suggest 5 functions:

void folderWatch(string path,void function(string) F)
void folderWatchAsync(string path,void function(string) F)
void fileWatch(string path,void function() F)
void fileWatchAsync(string path,void function() F)
bool hasFileBeenModified(string path)()//returns true once per file modification, first call always returns true

Paths should be unix supporting, .. ~:$HOME/%appdata% /:root/C:

async version should make a thread automagicly

Passing along the full system api is irrelevant; idk why the implimations I saw did so

etc. etc.