Problem linking on Win32

[Lemmih]

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'.

-- 
Cheers,
  Lemmih