On 02/06/2009 00:30, John Lask wrote:

I hav a module that depends upon (binds to) the microsoft uuid.lib (libuuid.a) this is a static library which exports some labels such as IID_IPersistFile. I was playing around with trying to get it to work both with normal compiling via ghc and to dynamically load in ghci. As we know, ghci can't load static libraries and so was not able to resolve the linkage. I therefore decided to directly incorporate the objects of (libuuid.a) into the haskell .a and ghci .o file (ghci) . To do this I needed to ject --whole-archive libuuid.a --no-whole-archive (or alternatively the list of objects) into the link command at an appropriate point to enable the resolution of the linkage.

I have achieved my goal but only by constructing the list of objects to link entirely manually, constructing both the .a and .o for the haskell library manually. I am not satisfied with this solution as it is fragile wrt changes in the module structure of the library I have constructed.

Right, GHCi doesn't work very well with static libraries. You can extract the contents of libuuid.a into a single .o file, and link this in - it sounds like that's what you're doing. In order to be able to use this without manual hackery, you will need to construct a Haskell package that only tries to link libuuid.a when in batch-linking mode (not GHCi). I think you can do this by given an empty extra-ghci-libraries field. And then you'll need to add uuid.o to the command line when starting GHCi. Cheers, Simon

jvl

----- Original Message ----- From: "Simon Marlow" To: "John Lask" Cc: Sent: Monday, June 01, 2009 9:15 PM Subject: Re: ghc - force library search order

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On 29/05/2009 15:19, John Lask wrote:

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----- Original Message ----- From: "Duncan Coutts" To: "John Lask" Sent: Friday, May 29, 2009 8:09 PM Subject: Re: [Haskell-cafe] ghc - force library search order

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On Fri, 2009-05-29 at 18:08 +1000, John Lask wrote:

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I need to force a library to be searched for unresolved symbols after all other libraries have been searched, and I would rather not resort to constructing the linker command line directly. Is there a way to do this?

i.e. I want for example -lfoo to appear after all other haskell libraries and before system libraries (for example -lmsvcrt) once ghc has constructed the link command. i.e. how is it possible to coerce ghc into respecting dependencies between the libraries. GHC does a good job in general with native libraries, but there are allways corner cases.

I have a feeling this is not possible, but it dosn't hurt to ask.

No, there's currently no way to inject flags that come *after* the linker flags for the packages on the linker command line.

It might help if you describe at a higher level what it is you're trying to do. There might be a better way to achieve it.

Cheers, Simon