BSD-3-Clause licensed by Trystan Spangler
Maintained by Sönke Hahn, Simon Hengel, Andreas Abel
This version can be pinned in stack with:silently-,2399

Module documentation for

Hackage version silently on Stackage Nightly Stackage LTS version Cabal build


Silently is a package that allows you to run an IO action and prevent it from writing to stdout, or any other handle, by using silence. Or you can capture the output for yourself using capture.

For example, the program

 import System.IO.Silently

 main = do
   putStr "putStrLn: " >> putStrLn "puppies!"
   putStr "silenced: " >> silence (putStrLn "kittens!")
   putStrLn ""
   (captured, result) <- capture (putStr "wookies!" >> return 123)
   putStr "captured: " >> putStrLn captured
   putStr "returned: " >> putStrLn (show result)

will print:

 putStrLn: puppies!
 captured: wookies!
 returned: 123


Capturing/silencing might not work as expected if the action uses the FFI or conceals output under unsafePerformIO or similar unsafe operations.


Changes August 2022

  • Tested with GHC 7.0 - 9.4.1.
  • Remove remnants of GHC 6.x support.
  • Silence incomplete pattern matching warning, refactor code.
  • Add section about limitations to README. November 2021

  • Tested with GHC 7.0 - 9.2.
  • Silence warning caused by missing other-modules in cabal file.
  • Add README and CHANGELOG to dist. July 2019

No changelog for this and earlier versions.