Re: 'import ccall unsafe' and parallelism

Hi! On Thu, Aug 14, 2014 at 5:54 PM, Christian Höner zu Siederdissen < choener@tbi.univie.ac.at> wrote:

However, due to the way ghc handles unsafe imports, namely block everything else whenever 'cfun' is called, I happen to have only one active 'go'. Lets assume 'cfun' is cheap and would suffer from 'ccall safe' more than I'd be willing to pay.

Calls to unsafe functions do not block everything! Other Haskell threads can continue running on other capabilities (make sure you run your program with +RTS -N). However, make sure that the C function itself never blocks, or it might deadlock your program.