When to use os.exit(code, true)?

[Paul K <paulclinger@...>]

The documentation for Lua 5.2 says about the second parameter:

> If the optional second argument close is true, closes the Lua state before exiting.

Can someone comment on why it may be needed? The difference comes to
lua_close(L) call, but what are the implications in terms of garbage
collections/memory use when the Lua state is not closed? I thought
os.exit would terminate the host program, so why was the second
parameter introduced?

Paul.