Re: [Haskell-cafe] Re: Waiting for thread to finish

Bryan O'Sullivan wrote:

But wait, there's more! If you're using the threaded RTS, you often need to know how many threads you can run concurrently, for example to explicitly split up a compute-bound task. This value is exposed at runtime by the numCapabilities variable in the GHC.Conc module.

http://www.haskell.org/ghc/docs/latest/html/libraries/base-3.0.0.0/GHC-Conc....

This variable is new in GHC 6.8.1 (thanks, Simon!), so don't try to use it with an older release.

Hmm... I was *sure* this was exposed in Control.Concurrent already... but, apparently, no. It seems you can only get at it from GHC.Conc. That's kind of a pitty... oh well! ;-)