Question

我有一个类似的问题：Cabal can't find foreign library when building on NixOS

基本上我正在使用cabal2nix从包含以下内容的package.yaml中生成

：

extra-libraries:
  - libmnl

这将产生一个cabal.nix文件：

{ mkDerivation, base, bytestring, cereal, containers, hpack
, iproute, lens, libmnl, netlink, primitive
, resourcet, safe-exceptions, stdenv, transformers
}:
mkDerivation {
  pname = "relay";
  version = "0.1.0.0";
  src = ./.;
  libraryHaskellDepends = [
    base bytestring cereal containers iproute lens netlink
    primitive resourcet safe-exceptions transformers
  ];
  librarySystemDepends = [ libmnl ];
  libraryToolDepends = [ hpack ];
  testHaskellDepends = [
    base bytestring cereal containers iproute lens netlink
    primitive resourcet safe-exceptions transformers
  ];
  testSystemDepends = [ libmnl ];
  preConfigure = "hpack";
  homepage = "https://github.com/MatrixAI/Relay#readme";
  license = stdenv.lib.licenses.asl20;
}

如果我通过nix-shell进行输入，然后运行cabal configure。它抱怨找不到libmnl：

Resolving dependencies...
Configuring relay-0.1.0.0...
cabal: Missing dependency on a foreign library:
* Missing (or bad) C library: libmnl
This problem can usually be solved by installing the system package that
provides this library (you may need the "-dev" version). If the library is
already installed but in a non-standard location then you can use the flags
--extra-include-dirs= and --extra-lib-dirs= to specify where it is.If the
library file does exist, it may contain errors that are caught by the C
compiler at the preprocessing stage. In this case you can re-run configure
with the verbosity flag -v3 to see the error messages.

还在gcc -c test.c -lmnl内的此文件上运行nix-shell可以正常工作：

#include <libmnl/libmnl.h>

int main() { return 0; }

所以为什么阴谋集团找不到libmnl，但是gcc却可以在nix-shell中轻松找到它。

使用-v3运行时，似乎试图链接到-llibmnl。但是正确的链接应该是-lmnl。这似乎很成问题，是否有办法告诉cabal与标记-lmnl而不是-llibmnl链接？

我发现，如果我编辑Cabal文件并更改extra-libraries指向mnl而不是libmnl，则可以通过更改Cabal尝试链接的方式来工作。但是，cabal2nix然后在取package.yaml时会产生libmnl，这是Nix提供的正确包装属性。看来extra-libraries应该是mnl，而cabal.nix应该是libmnl。

Answer 1

基本上，extra-libraries需要使用mnl而不是libmnl。然后，在使用cabal2nix时，它需要将libmnl包映射到mnl属性。上游cabal2nix映射mnl到libmnl commit：https://github.com/NixOS/cabal2nix/issues/413#event-2257811946

解决了这个问题。

使用nix-shell用cabal查找外国图书馆

1 个答案: