How do I pass C compiler flags in a Haskell Stack package.yaml

May 16, 2023

I’m working on a Haskell project involving some FFI, and I keep making small typos in the names of C functions in my Haskell code, which due to implicit function declaration, results in a warning, but not an error.

I’d like to pass -Werror-implicit-function-declaration to the gcc arguments, in order to turn these warnings into errors.

I’m using Haskell Stack, and it’s not obvious to me what I ought to add to my package.yaml in order to do this? What field should I add?

>Solution :

Looking at some of my local projects, here’s one example:

library:
    exposed-modules:
    - ...
    source-dirs:
    - ...
    ghc-options:
    - ...
    pkg-config-dependencies:
    - glib-2.0
    extra-lib-dirs:
    - /Workspace/INSTALL/lib
    include-dirs:
    - ./native
    - /Workspace/INSTALL
    c-sources:
    - ./native/*.c
    cc-options:
    - -O3 -fPIC -g3 -Wall -pedantic -Wno-variadic-macros -Werror

You can find the full reference documentation at https://github.com/sol/hpack.