Ketil Malde writes:

Either rename your modified version to 2.4 (or similar), specify the exact version in your *application's* cabal file,

..or you could compile your application specifying the package explicitly, using "-package unix-2.2.0.0" (and all the other packages, normally supplied by Cabal or ghc --make).

or use "ghc-pkg hide" to hide version 2.3.0.0 from view.

-k -- If I haven't seen further, it is by standing in the footprints of giants

Right I am just trying to rebuild the unix package. No matter what version is present in the unix.cabal file, runhaskell Setup.hs configure produces an error concerning unix-2.3.0.0 Starting to get really frustrated over this. I just want to build a Unix package test case .. and now I can't even build the unix package itself. ghc-pkg seems to be at the center of this problem because the problem seems to have to deal with the package database. 1) On Linux(Ubuntu) where is the package database? 2) If ghc-pkg is indeed a Haskell program, how can I get the source to better understand the problem I am encountering on my own? On Fri, Apr 11, 2008 at 9:33 AM, Brent Yorgey wrote:

On Fri, Apr 11, 2008 at 3:11 AM, Ketil Malde wrote:

...

"Galchin, Vasili" writes:

...

...

ghci :m System.Posix

I am getting the wrong version of the Unix package. I know this to be true because I did ghc-pkg latest unix

and got unix-2.3.0.0

I want unix.2.2.0.0 because this version has changes that I made

Naturally, you'll get 2.3.0.0, since it has the highest version number!

Either rename your modified version to 2.4 (or similar), specify the exact version in your *application's* cabal file, or use "ghc-pkg hide" to hide version 2.3.0.0 from view.

Actually, I'm pretty sure that Cabal does not take the visibility states of packages into account when selecting packages to fulfill dependencies, so ghc-pkg hide will not actually work.

-Brent