#9498: GHC links against unversioned .so files -------------------------------------+------------------------------------- Reporter: Kritzefitz | Owner: Type: feature | Status: new request | Milestone: Priority: low | Version: 7.6.3 Component: Compiler | Keywords: Debian (FFI) | Architecture: Unknown/Multiple Resolution: | Difficulty: Unknown Operating System: Linux | Blocked By: Type of failure: Other | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by thomie): Kritzefitz: thank you for the report. I am adding an example here for later reference. Please let me me know if there are any mistakes in the text below, I just learned this stuff tonight. On Ubuntu 14.04, `libbsd.so` (unversioned) is a symbolic link to the file `libbsd.so.0.6.0` (versioned). That symbolic link is created by the `libbsd-dev` (dev) package, while the library file is installed by the `libbsd0` (runtime) package. {{{ $ ll /usr/lib/x86_64-linux-gnu/libbsd.so lrwxrwxrwx 1 root root 37 Mar 20 2014 /usr/lib/x86_64-linux-gnu/libbsd.so -> /lib/x86_64-linux-gnu/libbsd.so.0.6.0 $ dpkg -S /usr/lib/x86_64-linux-gnu/libbsd.so libbsd-dev: /usr/lib/x86_64-linux-gnu/libbsd.so $ dpkg -S /lib/x86_64-linux-gnu/libbsd.so.0.6.0 libbsd0:amd64: /lib/x86_64-linux-gnu/libbsd.so.0.6.0 }}} This is a small program (called `testbsd.hs`) that calls a function in the libbsd library via the foreign function interface: {{{#!haskell module Main where import Foreign.C.Types foreign import ccall "arc4random" version :: CUInt main = print version }}} GHC links this program to `libbsd.so.0`, not `libbsd.so.0.6.0`, so the dev package will be needed to run it: {{{ $ ghc --make -lbsd testbsd.hs [1 of 1] Compiling Main ( testbsd.hs, testbsd.o ) Linking testbsd ... $ ldd testbsd ... libbsd.so.0 => /lib/x86_64-linux-gnu/libbsd.so.0 (0x00007faef5c2c000) ... $ ./testbsd 1131902945 }}} Note that some runtime packages do create the link from the unversioned to the versioned library themselves. This seems to be in particular true for all libraries in the `/lib/` directory. For example for `libpng`: {{{ $ ll /lib/x86_64-linux-gnu/libpng12.so.0 lrwxrwxrwx 1 root root 18 Apr 1 2014 /lib/x86_64-linux-gnu/libpng12.so.0 -> libpng12.so.0.50.0 $ dpkg -S /lib/x86_64-linux-gnu/libpng12.so.0.50.0 libpng12-0:amd64: /lib/x86_64-linux-gnu/libpng12.so.0.50.0 $ dpkg -S /lib/x86_64-linux-gnu/libpng12.so.0 libpng12-0:amd64: /lib/x86_64-linux-gnu/libpng12.so.0 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9498#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler