With the readline package from sunfreeware my ldd output is now $ ldd /usr/local/lib/ghc-6.8.2/ghc-6.8.2 librt.so.1 => /lib/librt.so.1 libreadline.so.5 => /usr/local/lib/libreadline.so.5 libncurses.so.5 => /usr/gnu/lib/libncurses.so.5 libdl.so.1 => /lib/libdl.so.1 libm.so.2 => /lib/libm.so.2 libgmp.so.3 => /usr/lib/libgmp.so.3 libpthread.so.1 => /lib/libpthread.so.1 libc.so.1 => /lib/libc.so.1 libgcc_s.so.1 => /usr/sfw/lib/libgcc_s.so.1 $ ldd /usr/local/lib/libreadline.so.5 warning: ldd: /usr/local/lib/libreadline.so.5: is not executable libgcc_s.so.1 => /usr/sfw/lib/libgcc_s.so.1 libc.so.1 => /lib/libc.so.1 libm.so.2 => /lib/libm.so.2 This is on Solaris Express Developer Edition 9/07.