id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,os,architecture,failure,difficulty,testcase,blockedby,blocking,related
1018,ghci dynamic loading of X11 - unknown symbol `_printf$LDBLStub',ykardia,,"Hello.

I have a problem with using ghci to dynamically load the X11 library on Mac OS X.

I create the following file:
-- test.hs --
module Main where
import Graphics.X11.Xlib
main = do print ""Hello, world!""
-------------

When I compile this with ghc --make test.hs, I get an executable that
is properly linked and works.

With dynamic loading, there are two issues:

1) A minor issue (easy workaround):
When I try to load this with ghci, i.e.
----------------
$ ghci test.hs
[... ascii graphics ...]
Loading package base ... linking ... done.
Ok, modules loaded: Main.
Prelude Main> main
Loading package X11-1.1 ... can't load .so/.DLL for: X11 (dlopen(libX11.dylib, 10): image not found)
----------------
I can fix this by running ghci setting DYLD_LIBRARY_PATH=/usr/X11R6/lib, which is where the Apple X11 lives.

2) Maybe a more serious issue?
----------------
$ DYLD_LIBRARY_PATH=/usr/X11R6/lib ghci test.hs
[... ascii graphics ...]
Loading package base ... linking ... done.
Ok, modules loaded: Main.
Prelude Main> main
Loading package X11-1.1 ... linking ... <interactive>: 
/opt/local/lib/ghc-6.6/HSX11_cbits.o: unknown symbol `_printf$LDBLStub'
ghc-6.6: unable to load package `X11-1.1'
----------------

Issue (1) is probably trivial, I am only pointing it out in case it is related to issue (2).

When I pointed this out on darcs-users, there were some suggestion that this might be due to SystemStubs not being linked in, or some problem with the compiler - apparently X11 is meant to be compiled with gcc 3.3, and it should work if compiled with gcc 4 as long as SystemStubs is linked in (?).

I have replicated this with the following combinations of software and hardware:
Mac OS X 10.4.8, dual G5, Xcode 2.4.1 (gcc 4.0.1), Apple X11 1.1.3,
macports ghc 6.6_1

Mac OS X 10.4.8, dual G5, Xcode 2.3 (gcc 4.0.1), Apple X11 1.1.2,
macports ghc 6.6_1

Mac OS X 10.4.8, dual G5, Xcode 2.3 (gcc 4.0.1), Apple X11 1.1.2,
binary distribution of ghc 6.6 for Mac OS X.

Mac OS X 10.4.8, G4 (Powerbook), Xcode 2.3 (gcc 4.0.1), Apple X11 1.1.2,
macports ghc 6.6_1

What's wrong?",bug,closed,normal,6.6.1,GHCi,6.6,fixed,"X11, dynamic loading",wolfgang.thaller@… gwright@…,MacOS X,powerpc,,Unknown,,,,