Florian Weimer [Friday 2 June 2006] :
 >
 > Is it possible to prevent the heap from being compacted, 

Yes. cf the function Gc.set

  Gc.set { (Gc.get()) with Gc.max_overhead = max_int }

 > or pin individual objects?

AFAIK, no


 > Currently, I copy all strings used in such a scenario, but this
 > adds quite a bit of overhead.

Mind that your strings need to be in the major heap for the
no-heap-compaction approach to work. To ensure this, your strings must
be long enough or you should call Gc.minor () before calling the C
function.

-- 
   Olivier