Hi all,
I fear I might be unaware of something I should be. Say I have a file
objc_util.m with the following contents:
#include
void ns_log(const char *s) {
NSString *str = [NSString stringWithUTF8String:s];
NSLog(@"%@", str);
}
I also have a file Main.hs with contents:
{-# LANGUAGE ForeignFunctionInterface #-}
module Main where
import Foreign.C.Types
import Foreign.C.String
foreign import ccall "ns_log" cNSLog :: CString -> IO ()
nsLog s = withCString s cNSLog
I compile objc_util.m with:
gcc -c objc_util.m
And then I try to open it up in GHCi.
ghci objc_util.o Main.hs -framework Foundation
I add the flag '-frame Foundation' in the hopes that symbols in objc_util.o
will get resolved
dynamically.
However I get:
GHCi, version 7.8.3: http://www.haskell.org/ghc/ :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Loading object (static) objc_util.o ... ghc: panic! (the 'impossible'
happened)
(GHC version 7.8.3 for x86_64-apple-darwin):
Loading temp shared object failed:
dlopen(/var/folders/pv/pfxcyy117v31vt6lsshtgr_w0000gn/T/ghc33546_0/ghc33546_1.dylib,
9): Symbol not found: _OBJC_CLASS_$_NSString
Referenced from: /var/folders/pv/pfxcyy1
17v31vt6lsshtgr_w0000gn/T/ghc33546_0/ghc33546_1.dylib
Expected in: flat namespace
in
/var/folders/pv/pfxcyy117v31vt6lsshtgr_w0000gn/T/ghc33546_0/ghc33546_1.dylib
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
However, I have found a work around to this. If I do this:
ln -s /System/Library/Frameworks/Foundation.framework/Foundation
Foundation.o
and then run
ghci Foundation.o objc_util.o Main.hs
I get this:
GHCi, version 7.8.3: http://www.haskell.org/ghc/ :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Loading object (static) Foundation.o ... done
Loading object (static) objc_util.o ... done
final link ... done
Everything has worked! And I can happily run 'nsLog' from GHCi and have it
appear in the
'Console' app.
However, it doesn't seem like I should have to do this. Where am I going
wrong?
Sean
