Problem linking on Win32

[Lemmih]

On 10/10/06, Jason Dagit <dagit at codersbase.com> wrote:
> On 10/9/06, Lemmih <lemmih at gmail.com> wrote:
> > On 10/9/06, Jason Dagit <dagit at codersbase.com> wrote:
> > > Hello,
> > >
> > > I have a program and I'd like to permanently change the default RTS
> > > options.  According to the GHC manual I can do that by linking with a
> > > snippet of C code:
> > > http://www.haskell.org/ghc/docs/latest/html/users_guide/runtime-control.html
> > >
> > > Look at section 4.14.5 at the bottom of the page.
> > >
> > > I can't seem to get cabal to link my program together so that my
> > > custom rts options take affect.  To help demonstrate I've created a
> > > minimal test case:
> > >
> > > ------------- oom.cabal -------------------
> > > name: OutOfMemory
> > > version: 0.1
> > > cabal-version: -any
> > > license: AllRightsReserved
> > > license-file: ""
> > > build-depends: base -any
> > > c-sources: rtsoptions.c
> > > exposed-modules: Main
> > >
> > > Executable: oom
> > > Main-is: Main.hs
> > > ------------- end oom.cabal -----------
> > >
> > > --------------- Main.hs ---------------------
> > > module Main where
> > >
> > > main :: IO ()
> > > main = print $ foldl (+) 0 [1..100000000]
> > > --------------- End Main.hs --------------
> > >
> > > /* rtsoptions.c */
> > > char *ghc_rts_opts = "-M1024M -K256M";
> > > /* end rtsoptions.c */
> > >
> > > Also using the standard Setup.lhs:
> > > #! /usr/bin/runghc
> > >
> > > \begin{code}
> > > import Distribution.Simple
> > > main = defaultMain
> > > \end{code}
> > >
> > > When build and run this I get:
> > > C:\projects\tmp>runghc Setup.lhs build
> > > Preprocessing library OutOfMemory-0.1...
> > > Preprocessing executables for OutOfMemory-0.1...
> > > Building OutOfMemory-0.1...
> > > [1 of 1] Compiling Main             ( Main.hs, dist\build\oom\oom-tmp/Main.o )
> > > Linking dist\build\oom\oom.exe ...
> > >
> > > C:\projects\tmp>dist\build\oom\oom.exe
> > > Heap exhausted;
> > > Current maximum heap size is 268435456 bytes (256 Mb);
> > > use `+RTS -M<size>' to increase it.
> > >
> > > On the other hand, if I build rtsoptions.c manually and add it to the
> > > ghc-options line in the .cabal file it does build and run until in
> > > needs more than 976Mb (showing that the default RTS options are indeed
> > > different).
> >
> > Add the C source to the executable instead of the library. In other
> > words, move the 'c-sources' under 'main-is'.
>
> Ah yes.  I feel silly now to have been stumped on this so long.  As
> soon as you say it, it makes instant sense since Cabal conceptually
> keeps the library stanza separate from executable stanzas.
>
> Perhaps it would help if cabal throw a warning when the first stanza
> is not separate from the 'meta data' by a blank line.  So that the
> library stanza is always standing by itself too.  Just a thought.

Don't feel silly; silently ignoring the 'c-sources' is a bug. The bug
has been fixed in recent versions of Cabal where configuring your
project would have resulted in an error message.

-- 
Cheers,
  Lemmih