never used in multi-threaded situation.
Erm, nearly all my code in Haskell is multi-threaded. One of the main reasons why I am using haskell is the low-cost light weight multi-threading. Surely this is a big win for Haskell on SMP/Numa machines - which are surely the future - as even Intel have realised they can't just keep ramping up clock speeds and have gone multi-core for their next pentium iteration. Just look at the benchmarks for the multi-cpu opteron machines! I would hesitate to make any type unsafe for multi-threading by default - I think all the guards should be in as standard ... maybe a compile time (or run-time) flag to replace the guards with NO-OPS for single CPU machines might be a sensible option. Regards, Keean Schupke.