Re: [Caml-list] Queens examples

[Xavier Leroy <Xavier.Leroy@inria.fr>]

> Running the queens and queens_lazy basic examples in OCamlWin gives 
> a stack overflow with board size of 12 x 12.   The queens_lazy 
> example is set-up to do 12 x 12, so it crashes right out of the box.
> Does OCaml often produce such errors?  Is there a trick to preventing
> these errors that was overlooked in writing these examples?

Just to complement the detailed replies already made on this list:
OCaml would happily grow the stack until all the available memory
(physical and virtual) is exhausted.  However, excessive stack
consumption is often the sign of a programming error (recursion that
misses the base case), and exhausting all the memory before reporting
it is not nice, so OCaml implements a soft limit on the size of the
stack.  By default, it's 1 megabyte, but it can be changed from the
command line (the CAMLRUNPARAM variable) or even from within the
program or the interactive system:

        Gc.set {(Gc.get()) with Gc.stack_limit = 4 * 1024 * 1024}

The above bumps the limit to 4 mega-words (16 mega-bytes), and is
enough to run the Queens example with size 12.

Hope this helps,

- Xavier Leroy
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