Is this not the lisp "future" function?

That's rather similar to how Java-style threading is done in the case where the "master"
thread and the child task share no data. Presumably that's always the case in lisp, given its
functional design.

Sure, the Java approach is uglier and more verbose, but the principle remains practically the
same. You can use a callback or (with the TrollTech Qt approach) event in the event loop to
detect completion. Or you can just poll for completion by testing an instance variable of the
thread subclass.

http://java.sun.com/j2se/1.3/docs/api/java/lang/Thread.html

A similar approach can be used in C++ with Qt. It's really rather nice, and makes threading
quite sane for launching independent deferred calls that should produce a result "later".