From 0caf5b2378412752a34094a1e89b706956e37e7b Mon Sep 17 00:00:00 2001
From: Greg Burd <gburd@symas.com>
Date: Tue, 12 Sep 2023 10:09:05 -0400
Subject: [PATCH] hello-c from NixOS/templates

https://github.com/NixOS/templates/blob/master/c-hello
---
 Makefile.in  |  13 ++++++
 configure.ac |   4 ++
 flake.nix    | 116 +++++++++++++++++++++++++++++++++++++++++++++++++++
 hello.c      |   6 +++
 4 files changed, 139 insertions(+)
 create mode 100644 Makefile.in
 create mode 100644 configure.ac
 create mode 100644 flake.nix
 create mode 100644 hello.c

diff --git a/Makefile.in b/Makefile.in
new file mode 100644
index 0000000..f937d5a
--- /dev/null
+++ b/Makefile.in
@@ -0,0 +1,13 @@
+prefix = @prefix@
+exec_prefix = @exec_prefix@
+bindir = @bindir@
+
+hello: hello.c
+	$(CC) -Wall -O3 -o hello hello.c
+
+clean:
+	rm -f hello
+
+install: hello
+	install -d $(bindir)
+	install -t $(bindir) hello
diff --git a/configure.ac b/configure.ac
new file mode 100644
index 0000000..347364e
--- /dev/null
+++ b/configure.ac
@@ -0,0 +1,4 @@
+AC_INIT([Hello], 1.0)
+AC_PROG_CC
+AC_CONFIG_FILES(Makefile)
+AC_OUTPUT
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..2d4bb34
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,116 @@
+{
+  description = "An over-engineered Hello World in C";
+
+  # Nixpkgs / NixOS version to use.
+  inputs.nixpkgs.url = "nixpkgs/nixos-21.05";
+
+  outputs = { self, nixpkgs }:
+    let
+
+      # to work with older version of flakes
+      lastModifiedDate = self.lastModifiedDate or self.lastModified or "19700101";
+
+      # Generate a user-friendly version number.
+      version = builtins.substring 0 8 lastModifiedDate;
+
+      # System types to support.
+      supportedSystems = [ "x86_64-linux" "x86_64-darwin" "aarch64-linux" "aarch64-darwin" ];
+
+      # Helper function to generate an attrset '{ x86_64-linux = f "x86_64-linux"; ... }'.
+      forAllSystems = nixpkgs.lib.genAttrs supportedSystems;
+
+      # Nixpkgs instantiated for supported system types.
+      nixpkgsFor = forAllSystems (system: import nixpkgs { inherit system; overlays = [ self.overlay ]; });
+
+    in
+
+    {
+
+      # A Nixpkgs overlay.
+      overlay = final: prev: {
+
+        hello = with final; stdenv.mkDerivation rec {
+          pname = "hello";
+          inherit version;
+
+          src = ./.;
+
+          nativeBuildInputs = [ autoreconfHook ];
+        };
+
+      };
+
+      # Provide some binary packages for selected system types.
+      packages = forAllSystems (system:
+        {
+          inherit (nixpkgsFor.${system}) hello;
+        });
+
+      # The default package for 'nix build'. This makes sense if the
+      # flake provides only one package or there is a clear "main"
+      # package.
+      defaultPackage = forAllSystems (system: self.packages.${system}.hello);
+
+      # A NixOS module, if applicable (e.g. if the package provides a system service).
+      nixosModules.hello =
+        { pkgs, ... }:
+        {
+          nixpkgs.overlays = [ self.overlay ];
+
+          environment.systemPackages = [ pkgs.hello ];
+
+          #systemd.services = { ... };
+        };
+
+      # Tests run by 'nix flake check' and by Hydra.
+      checks = forAllSystems
+        (system:
+          with nixpkgsFor.${system};
+
+          {
+            inherit (self.packages.${system}) hello;
+
+            # Additional tests, if applicable.
+            test = stdenv.mkDerivation {
+              pname = "hello-test";
+              inherit version;
+
+              buildInputs = [ hello ];
+
+              dontUnpack = true;
+
+              buildPhase = ''
+                echo 'running some integration tests'
+                [[ $(hello) = 'Hello Nixers!' ]]
+              '';
+
+              installPhase = "mkdir -p $out";
+            };
+          }
+
+          // lib.optionalAttrs stdenv.isLinux {
+            # A VM test of the NixOS module.
+            vmTest =
+              with import (nixpkgs + "/nixos/lib/testing-python.nix") {
+                inherit system;
+              };
+
+              makeTest {
+                nodes = {
+                  client = { ... }: {
+                    imports = [ self.nixosModules.hello ];
+                  };
+                };
+
+                testScript =
+                  ''
+                    start_all()
+                    client.wait_for_unit("multi-user.target")
+                    client.succeed("hello")
+                  '';
+              };
+          }
+        );
+
+    };
+}
diff --git a/hello.c b/hello.c
new file mode 100644
index 0000000..d67cd5d
--- /dev/null
+++ b/hello.c
@@ -0,0 +1,6 @@
+#include "stdio.h"
+
+int main(int argc, char * * argv)
+{
+    printf("Hello Nixers!\n");
+}