Distribution.PkgConfigVersionHook

     main :: IO ()
     main =
       defaultMainWithHooks $
         simpleUserHooks
           & addHook
             (mkSettings "nix-store")
               { macroName = NIX,
                 flagPrefixName = "nix"
               }
 

The above will look for a pkg-config package nix-store, and then

• Define CPP, C and C++ macros

  • NIX_MAJOR, an integer
  • NIX_MINOR, an integer
  • NIX_PATCH, an integer; 0 if missing
  • NIX_IS_AT_LEAST(major,minor,patch), returning true when the discovered version >= the specified version
• Set or unset flags like `nix-2_4` so that the flag is true when the discovered version is at least the version in the flag's name.

Documentation

addHook :: Settings -> UserHooks -> UserHooks

Hook into Cabal to provide pkg-config metadata. Can be applied multiple times to support multiple packages.

mkSettings :: String -> Settings

Derive a default Settings value from just a pkg-config package name.

data Settings

How the metadata for a pkg-config package should be made available to the cabal file.

Constructors

Settings

Fields

• pkgConfigName :: String

  Name of the package; used for querying pkg-config.

• macroName :: String

  Name to use in the Haskell CPP and C/C++ preprocessor macros.

  For example, `pkgConfigName = FOO` will set the macros

  • FOO_MAJOR

  • FOO_MINOR

  • FOO_PATCH

  • FOO_IS_AT_LEAST(major, minor, patch)

• flagPrefixName :: String

  Name to use when setting flag values in the cabal file.

  Flags named with this prefix, followed by a dash, followed by a major version number, an underscore and a minor version number will be set when the detected package is at least that version.

composeConfHook :: Settings -> ((GenericPackageDescription, a) -> ConfigFlags -> IO b) -> (GenericPackageDescription, a) -> ConfigFlags -> IO b

Extend the value of confHook. It's what powers addHook.