diff --git a/Haskintex.hs b/Haskintex.hs
--- a/Haskintex.hs
+++ b/Haskintex.hs
@@ -305,7 +305,7 @@
 
 -- | Run haskintex with the given arguments. For example:
 --
--- > haskintex ["-visible","-overwrite"]
+-- > haskintex ["-visible","-overwrite","foo.htex"]
 --
 --   Useful if you want to call /haskintex/ from another program.
 --   This function does /not/ do any system call.
diff --git a/examples/threaded.htex b/examples/threaded.htex
new file mode 100644
--- /dev/null
+++ b/examples/threaded.htex
@@ -0,0 +1,18 @@
+\documentclass{article}
+\begin{document}
+\begin{writehaskell}
+
+import Text.LaTeX
+
+import Control.Concurrent
+import Control.Concurrent.MVar
+
+test :: IO String
+test = do
+  v <- newEmptyMVar
+  forkOS $ putMVar v "concurrent"
+  takeMVar v
+
+\end{writehaskell}
+I like to write \iohatex{fmap fromString test} programs.
+\end{document}
diff --git a/haskintex.cabal b/haskintex.cabal
--- a/haskintex.cabal
+++ b/haskintex.cabal
@@ -1,5 +1,5 @@
 name:                haskintex
-version:             0.4.0.0
+version:             0.4.1.0
 synopsis:            Haskell Evaluation inside of LaTeX code.
 description:
   The /haskintex/ (Haskell in LaTeX) program is a tool that reads a LaTeX file and evaluates Haskell expressions contained
@@ -24,6 +24,7 @@
                      examples/io.htex
                      examples/pragmas.htex
                      examples/string.htex
+                     examples/threaded.htex
 cabal-version:       >=1.10
 
 executable haskintex
@@ -32,7 +33,7 @@
   build-depends: base == 4.*
                , haskintex
   default-language: Haskell2010
-  ghc-options: -Wall
+  ghc-options: -Wall -threaded
 
 library
   default-language: Haskell2010