$ ocaml -I +pcre
        Objective Caml version 3.08.1

# #load "pcre.cma";;
# let rex = Pcre.regexp "(:?([a-z]+)\\s+)*";;
val rex : Pcre.regexp = <abstr>
# Pcre.extract_all ~rex "a b c d ee ff ";;

  (* Hangs, rapidly consuming memory.  Killed with ^C ... *)

Interrupted.
# Gc.full_major ();;
- : unit = ()

The Gc.full_major () doesn't recover any memory.

On a more general point, how do I access all the strings captured by
the inner brackets in a pattern like (:? (..)  )*  ?

Rich.

-- 
Richard Jones. http://www.annexia.org/ http://www.j-london.com/
Merjis Ltd. http://www.merjis.com/ - improving website return on investment
MOD_CAML lets you run type-safe Objective CAML programs inside the Apache
webserver. http://www.merjis.com/developers/mod_caml/