The GHC manual needs to specify what happens when you use -odir and hierarchical modules with --make. I posted to the list about this before but it was not resolved: http://www.haskell.org/pipermail/glasgow-haskell-users/2002-October/004178.h... Here is an example: . |-- Library | |-- Bar | | `-- Module.hs | `-- Foo | `-- Module.hs `-- Program |-- Program.hs `-- output Program.hs uses Bar.Module and Foo.Module. Then, doing cd to Program # ghc -i../Library --make Program ghc-5.04.2: chasing modules from: Program Compiling Bar.Module ( ../Library/Bar/Module.hs, ../Library/Bar/Module.o ) Compiling Foo.Module ( ../Library/Foo/Module.hs, ../Library/Foo/Module.o ) Compiling Main ( Program.hs, ./Program.o ) ghc: linking ... everything works fine. Using -odir: # ghc -i../Library -odir output --make Program ghc-5.04.2: chasing modules from: Program Compiling Bar.Module ( ../Library/Bar/Module.hs, output/Module.o ) Compiling Foo.Module ( ../Library/Foo/Module.hs, output/Module.o ) Compiling Main ( Program.hs, output/Program.o ) ghc: linking ... <LONG LINKER ERROR> Error, since both modules are compiled to the same file. This should not happen. What should be done about it? Solution 1: -odir is relative to the source directory (files will end up in Library/Bar/output/Module.o and Library/Foo/output/Module.o). This is a change of semantics from the earlier behaviour of -odir (files are put in another place). On the other hand, it may be more natural to put files relative to their source, like --make without -odir does. The question remains what to do if -odir is an absolute path. Solution 2: files put in -odir are put in directories (files will end up in Program/output/Bar/Module.o and Program/output/Foo/Module.o) This is also a slight change in semantics, since files are put in directories. May affect Makefiles that does "ar output/*.o" or similar. Solution 3: files put in -odir will have their full module name (files will end up in Program/Output/Bar.Module.o and Program/Output/Foo.Module.o) This is an ever lesser change in semantics, and is better than solution 2 in my opinion. I would recommend using solution 1 if the path name is relative and solution 3 if it's absolute. Regards, Martin -- Martin Norbäck d95mback@dtek.chalmers.se Kapplandsgatan 40 +46 (0)708 26 33 60 S-414 78 GÖTEBORG http://www.dtek.chalmers.se/~d95mback/ SWEDEN OpenPGP ID: 3FA8580B