IDL 8.4 adds a new class FolderWatch to watch a directory for changes to its files:

IDL> fw = folderwatch('.', lambdap(fw, info: print, info.file), /added)

Then if you drop a file into the current directory, for example test.txt, you should see:

IDL>
test.txt

The callback procedure, which I passed a lambda procedure[1] to in my example, takes two arguments: the FolderWatch object and an info structure with definition:

{ IDLFolderWatchInfo, file: '', added: 0B, modified: 0B, removed: 0B }

The object also has a USER_DATA property which allows you to store information that you might need in the callback routine.

  1. I think I’m going to like lambda routines. ??