On 15/02/2012 12:31, Eugene Crosser wrote:
Hello all,
I am new here, but I want to report what I suspect may be a problem.
I ran into it while using some third-party package from hackage on a 32bit Linux with ghc 7.4.1. I discovered that off_t fields in the .hsc files in the package where interpreted as 32bit words. I suspected that 64bit offsets should be used because even 32bit Linux has "largefile" support with 64bit offsets.
I found that earlier versions of hsc2hs included HsFFI.h into the generated C code, and HsFFI.h in turn indirectly includes ghcautoconf.h which has
#define _FILE_OFFSET_BITS 64
in it. So, if I build the .hsc files like this:
hsc2hs -i HsFFI.h filename.hsc
then off_t is 64bit and 64bit file manipulation syscalls are used. I did not check it but I think that earlier versions of hsc2hs where creating largefile-aware version of the code by default, because HsFFI.h was included in the code by default.
This is a simple test program:
==== checktypes.hsc ==== -- run like this: hsc2hs checktypes.hsc&& runhaskell checktypes.hs module Main where #include
main = do putStrLn $ show (#size off_t) ======================== $ hsc2hs checktypes.hsc&& runhaskell checktypes.hs 4 $ hsc2hs -i HsFFI.h checktypes.hsc&& runhaskell checktypes.hs 8
As I understand, this situation means that while the ghc itself and haskell programs compiled by it are largefile-capable, any third party modules that contain .hsc files are not. If I am right, this is probably not a good thing.
Please can some guru take a look at this issue?
Guru at your service :-) We discovered this during the 7.4 cycle: http://hackage.haskell.org/trac/ghc/ticket/2897#comment:12 Packages that were relying on `HsFFI.h` to define `_FILE_OFFSET_BITS` should no longer do this, instead they should use an appropriate autoconf script or some other method. See the `unix` package for an example of how to do this. It was really a mistake that it worked before. Cheers, Simon
See also: http://www.haskell.org/pipermail/glasgow-haskell-users/2009-February/016606.... http://www.haskell.org/pipermail/cvs-ghc/2011-September/065848.html
Thanks,
Eugene
_______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users