Hello all, My question is rather strange, maybe, even if simple: Does ghci always translates with "-O" option set on? I've done some measurements on an application using ghc and ghci. ghc compiled with no opmitization => program running real 988m59.260s user 989m1.325s sys 0m0.704s ghc compiled with optimization set on => program running real 15m54.343s user 15m54.168s sys 0m0.172s ghci alaways: 951.97 secs, 7445117252 bytes (which is 15m51.97sec) To be honest, I don't mind ghci optimizes always but saying it uses the same options as ghc is not entirely true and, for optimization, it's quite painful because one searches error where it is not. (/Understand, I was wondering why program compiled by ghc crashes and/or evaluates so long while running correctly and fast in ghci./) Dusan