Hello everyone, I have been trying to run a Haskell program of mine that does an extensive computation with very large amounts of data. I compiled the program with ghc --make. When I run it it terminates after some time with the message: Stack space overflow: current size 8388608 bytes. Use `+RTS -Ksize' to increase it. The program isn't that well written so the overflow did not surprise me, I expected that it might run out of memory. What did surprise me was the *stack* overflow. I do not use recursion in my program except for a couple of fold operations over very large lists. So I have a number of questions: 1) Which Haskell operations cost space on the stack, which cost space on the heap? I guess this is implementation dependent, so I looked into the GHC manual but did not find an answer. Where can I look these things up? 2) What could be possible sources of a stack overflow? (Apart from a recursive but not tail-recursive function.) 3) I tried using +RTS -K<size> as suggested, but these options do not seem to be passed through if I use --make. How can I use both, these compilation flags and --make? Thanks, Felix