I am checking out the computing music development library Euterpea, and I am trying to compile the following basic program: import Euterpea t251 :: Music Pitch t251 = let dMinor = d 4 wn :=: f 4 wn :=: a 4 wn gMajor = g 4 wn :=: b 4 wn :=: d 5 wn cMajor = c 4 bn :=: e 4 bn :=: g 4 bn in dMinor :+: gMajor :+: cMajor main = play t251 the program works fine inside ghci, but when I try to compile it using ghc test.hs I get the following error message: Linking test ... /usr/bin/ld: /home/fayong/.cabal/lib/PortMidi-0.1.3/ghc-7.6.3/libHSPortMidi-0.1.3.a(ptlinux.o): undefined reference to symbol 'pthread_create@@GLIBC_2.2.5' //lib/x86_64-linux-gnu/libpthread.so.0: error adding symbols: DSO missing from command line collect2: error: ld returned 1 exit status It seems to be a linking error but I don't know how to fix it. (I tried to pass -lpthread as an option but it didn't work) I installed Euterpea via cabal, on linux mint 17