Henrik Nilsson wrote:
[...] Well, ar does not support directories anyway, so if the objective here is to build a link library, the leaf names had better be distinct. (At least GNU make does seem to allow putting two object files with the same name into a link library if done as a single operation, but my guess is that doing so is asking for trouble.) [...]
Allowing leaf names to be equal is essential for the whole hierarchical module business! Otherwise you would get evil non-local interactions between different modules. And in practice it doesn't seem to be a problem for ar/ld, because the base package and the GLUT package have lots of examples for equal leaf names (see below). I'm not sure how ar/ld handle this exactly, but I guess it works because of an index in the archive. From the Linux ar man page: ... ar creates an index to the symbols defined in relocatable object modules in the archive when you specify the modi fier s. Once created, this index is updated in the archive whenever ar makes a change to its contents (save for the q update operation). An archive with such an index speeds up linking to the library, and allows rou tines in the library to call each other without regard to their placement in the archive. You may use nm -s or nm --print-armap to list this index table. If an archive lacks the table, another form of ar called ranlib can be used to add just the table. ... Newer ar versions to add this index automatically, other need an explicit ranlib. The GHC installation process takes care of that automatically. Cheers, S. --------------------------------------------------------------------------- Leaf name "clashes" in the current GHC version: libHSGLUT.a: Graphics.UI.GLUT.Window Graphics.UI.GLUT.Callbacks.Window libHSbase.a: Data.Array Foreign.Marshal.Array Data.Array.Base GHC.Base Data.Char Text.ParserCombinators.Parsec.Char Control.Monad.Error Foreign.C.Error Foreign.Marshal.Error System.IO.Error Text.ParserCombinators.Parsec.Error Control.Exception GHC.Exception Data.Array.IO GHC.IO System.IO Data.Int GHC.Int Control.Monad.ST.Lazy Data.STRef.Lazy Control.Monad.List Data.List GHC.List GHC.Posix Text.Regex.Posix Foreign.Ptr GHC.Ptr GHC.Read Text.Read Data.STRef GHC.STRef Control.Monad.ST Data.Array.ST GHC.ST GHC.Show Text.Show Data.Array.Storable Foreign.Storable GHC.Storable Control.Monad.ST.Strict Data.STRef.Strict Foreign.C.Types System.Posix.Types Debug.QuickCheck.Utils Foreign.Marshal.Utils GHC.Weak System.Mem.Weak