How to find the number of cores at runtime in Haskell

Question

Does Haskell have a method for determining the number of CPU cores present on a machine at runtime?

Answer 1

Yes, there is such a method. Code from "Real World Haskell": http://book.realworldhaskell.org/read/concurrent-and-multicore-programming.html

import GHC.Conc (numCapabilities)

main = putStrLn $ "number of cores: " ++ show numCapabilities