GSL dependency cblas in nix flake

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1

Using this flake

{
  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs";
    flake-utils.url = "github:numtide/flake-utils";
    zig-overlay.url = "github:mitchellh/zig-overlay";
  };

  outputs = inputs:
    let
      inherit (inputs) nixpkgs zig-overlay flake-utils gsl;
      systems = [ "x86_64-linux" ];
    in
    flake-utils.lib.eachSystem systems (system:
      let
        pkgs = import nixpkgs { inherit system; };
        zig = zig-overlay.packages.${system}.master;
        gsl = pkgs.gsl;
        blas = pkgs.blas;
      in
      {
        devShells.default = pkgs.mkShell {
          packages = [ zig gsl blas ];
        };
      });
}

I want to compile this C program using the Zig toolchain:

#include <gsl/gsl_cdf.h>
#include <stdio.h>

int main(){
    double bottom_tail = gsl_cdf_gaussian_P(-1.96, 1);
    printf("Area betweeen [-1.96, 1.96]: %g\n", 1 - 2*bottom_tail);
}

via

zig build-exe main_gsl.c -lgsl -lc

but I get a lot of undefined cblas_* from gsl.so

error: ld.lld: undefined reference due to --no-allow-shlib-undefined: cblas_ctrmv
    note: referenced by /nix/store/wh63z2hi25bkiajrg6rzj9pfpyvwp0wy-gsl-2.7.1/lib/libgsl.so
error: ld.lld: undefined reference due to --no-allow-shlib-undefined: cblas_zswap
    note: referenced by /nix/store/wh63z2hi25bkiajrg6rzj9pfpyvwp0wy-gsl-2.7.1/lib/libgsl.so
...

so the actual question, how can I pull in the BLAS dependency for GSL? I tried above with blas package, but initially thought that the dependency would be pulled in with GSL already?

2

Well, I gave up too early. Got this fixed via

zig build-exe main_gsl.c -lgsl -lc -lblas

and added gsl and blas to the mkShell nativeBuildInputs for good measure.

Edit: looked at the wrong output, still not resolved, but I got closer, now symbol lookup fails with

./main_gsl: symbol lookup error: /nix/store/wh63z2hi25bkiajrg6rzj9pfpyvwp0wy-gsl-2.7.1/lib/libgsl.so.27: undefined symbol: cblas_ctrmv