On Nov 29, 2007, at 13:38 , Andrew Coppin wrote:
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.html#v%3AnumCapabilities
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! ;-)
It's internal implementation foo; why would it be part of an interface intended to be reasonably portable? -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery@kf8nh.com system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH