Any advice? If you can't even install a package with no dependencies except base, I think there's trouble: $ cabal install cmath Resolving dependencies... Configuring cmath-0.3... Preprocessing library cmath-0.3... Building cmath-0.3... [1 of 1] Compiling Foreign.C.Math.Double ( dist/build/Foreign/C/Math/Double.hs, dist/build/Foreign/C/Math/Double.o ) /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc: In function ‘s2sB_ret’: /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc:2850:0: error: ‘gamma’ undeclared (first use in this function) /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc:2850:0: error: (Each undeclared identifier is reported only once /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc:2850:0: error: for each function it appears in.) /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc: In function ‘s2t0_ret’: /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc:2896:0: error: ‘gamma’ undeclared (first use in this function) /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc: In function ‘s2uH_ret’: /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc:3088:0: error: ‘isinf’ undeclared (first use in this function) /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc: In function ‘s2v6_ret’: /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc:3134:0: error: ‘isinf’ undeclared (first use in this function) /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc: In function ‘s2vv_ret’: /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc:3180:0: error: ‘isnan’ undeclared (first use in this function) /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc: In function ‘s2vU_ret’: /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc:3226:0: error: ‘isnan’ undeclared (first use in this function) /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc: In function ‘s2wj_ret’: /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc:3272:0: error: ‘finite’ undeclared (first use in this function) /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc: In function ‘s2wI_ret’: /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc:3318:0: error: ‘finite’ undeclared (first use in this function) /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc: In function ‘s2Kh_ret’: /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc:4856:0: error: ‘significand’ undeclared (first use in this function) /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc: In function ‘s2KG_ret’: /var/folders/+p/+pUVycVKFDWsYP8YiYnM3k+++TM/-Tmp-/ghc70799_0/ghc70799_0.hc:4902:0: error: ‘significand’ undeclared (first use in this function) cabal: Error: some packages failed to install: cmath-0.3 failed during the building phase. The exception was: ExitFailure 1 Thanks for any help! amindfv / Tom