On 6 January 2011 16:11, Joe Bruce
Thanks, Max. I had seen that thread already, but I don't understand how it helps me. I'm on a x64 mac and I have both an i386 and x64 version of readline installed (via macports install readline +universal). Perhaps cabal is choosing the wrong one. How do I find out? How do I tell it which to use? And which do I want it to use?
Well, MacPorts +universal should install fat binaries that include both x86 and x64. On my machine: """ mbolingbroke@c089 ~ $ file /opt/local/lib/libreadline.5.0.dylib /opt/local/lib/libreadline.5.0.dylib: Mach-O universal binary with 2 architectures /opt/local/lib/libreadline.5.0.dylib (for architecture i386): Mach-O dynamically linked shared library i386 /opt/local/lib/libreadline.5.0.dylib (for architecture x86_64): Mach-O 64-bit dynamically linked shared library x86_64 mbolingbroke@c089 ~ $ file /opt/local/lib/libreadline.a /opt/local/lib/libreadline.a: Mach-O universal binary with 2 architectures /opt/local/lib/libreadline.a (for architecture i386): current ar archive random library /opt/local/lib/libreadline.a (for architecture x86_64): current ar archive random library """ GHC on OS X builds 32 bit executables, so you need to link against these binaries. Long story short: $ cabal unpack readline Then edit readline.cabal to add this line to the end: extra-lib-dirs: /opt/local/lib (You must indent it to put it in the "library" section). Finally: $ sudo cabal install --configure-option=--with-readline-includes="/opt/local/include" --configure-option=--with-readline-libraries="/opt/local/lib" It will now work. You can try it by opening ghci and typing: System.Console.Readline.readline "Command Me> " An alternative to editing the cabal file would have been to link to the Macports fat-binary libreadline.a from the OS X system library directories (maybe /usr/lib or /usr/local/lib). Cheers, Max