On Wed, Jun 15, 2011 at 2:16 AM, Simon Marlow <marlo...@gmail.com> wrote: > On 14/06/2011 17:57, Jason Dagit wrote: >> >> On Tue, Jun 14, 2011 at 4:26 AM, Simon Marlow<marlo...@gmail.com> wrote: >>> >>> On 12/06/2011 20:17, Jason Dagit wrote: >>>> >>>> On Sun, Jun 12, 2011 at 11:45 AM, Brandon Allbery<allber...@gmail.com> >>>> wrote: >>>>> >>>>> On Sun, Jun 12, 2011 at 14:31, Jason Dagit<dag...@gmail.com> wrote: >>>>>> >>>>>> If I build the C library as a .a, then ghci comlains that it cannot >>>>>> open the .dylib. My first question is: Why does ghci need a .dylib >>>>>> and does it really use it? >>>>> >>>>> Static libraries are... static. ghci would have to rebuild itself >>>>> against the static archive to use it; that's how static archives work. >>>>> Dynamic libraries are dynamic because they can be loaded at runtime >>>>> instead of compile time. >>>> >>>> Interesting. When I use dtruss to see what files ghci opens, it >>>> definitely opens .a files. That gave me the impression it knows how >>>> to open a .a and use it at run-time. >>> >>> GHC as of version 7.0 can load .a files into GHCi. >>> >>>>>> When I build a dylib I get a [segfault when loading the code into >>>>>> ghci][2]. >>> >>> I don't know what the cause of that is - when you load a .dylib into >>> GHCi, >>> the normal system dynamic linker is used. >> >> How would you track it down? I'd really like to fix this and I don't >> mind debugging it, but I've tried all the things I could think of >> (valgrind, dtruss, gdb and printf). Valgrind didn't help because ghci >> couldn't read from stdin. gdb isn't so great because I was missing >> debug symbols for everything. >> >> I don't really believe it is an error in the RTS or the library code >> so it seems like gdb won't ever help here. >> >> Ideas? > > Can you build a simple .dylib, load it into GHCi and call it from Haskell? > If that works, then see if you can gradually evolve the tiny example > towards the real failure case and see at which point it fails.
I can try this. I was hesitant to go down that road simply because this dylib does work if I remove the memset and any code that writes to that area of memory. > Can you build GHC yourself? If so, you can link GHC with -debug, and that > will give you access to the debugging output from the linker (+RTS -Dl) and > gdb will have source information about the RTS. Building GHC myself is no problem. I usually do that on OSX anyway so that I can link with iconv from macports. This is the first time I've used the Haskell Platform version of GHC on osx. > I don't know who is generating those messages about "Reading symbols for > shared libraries ...", or the ones about "Could not find object file", maybe > those are generated by the system linker? I'm 99% sure those are from GDB. I don't see them unless I run ghci inside gdb. > Did you compile the source files with -fPIC? (I presume that's necessary, > but I don't know much about OS X). I've tried with each -fPIC and -fno-common. The makefile I use is linked in the original question, but here is the link again incase you want to look at it: https://github.com/dagit/GLFW-b/blob/master/Makefile The current flag configuration matches what is in the git repo for GLFW. When I tried with -fPIC I didn't notice any difference. Thanks, Jason _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe