added c-programs example with library+binary

Author: qknight

README.md

@@ -1,6 +1,17 @@
 # nix-shell workshop 
 
 ## normal c programs
+
+enter environment by typing `nix-shell` in ./c-programs afterwards
+change directory `cd main` and run `make`
+
+finally run `./main` to see the ultimate answer:
+
+    ./main 
+    hello world from the #cccamp2015, the answer is 
+    42
+
+
 ## go programs
 ## qt programs
 ## perl

c-programs/default.nix

@@ -0,0 +1,14 @@
+with import <nixpkgs> { };
+
+let
+  mylib = callPackage ./mylib.nix {};
+in
+
+stdenv.mkDerivation rec {
+  name = "myprogram-${version}";
+  version = "0.0.1";
+
+  buildInputs = [ mylib ];
+}
+
+

c-programs/main/Makefile

@@ -0,0 +1,4 @@
+all :
+	g++ main.cpp -l mylib -o main
+clean :
+	rm main

c-programs/main/main.cpp

@@ -0,0 +1,7 @@
+#include <iostream>
+#include <mylib.hpp>
+
+int main() {
+   std::cout << "hello world from the #cccamp2015, the answer is " << std::endl;
+   std::cout << mylib(23) << std::endl;
+}

c-programs/mylib.nix

@@ -0,0 +1,23 @@
+{stdenv}:
+
+stdenv.mkDerivation rec {
+  name = "mylib-1.0.0";
+
+  src = ./mylib; 
+
+  buildInputs = [ ];
+
+  installPhase = ''
+    mkdir -p $out/lib
+    mkdir -p $out/include
+    prefix=$out make install
+  '';
+
+  meta = {
+    description = "mylib";
+    homepage = "http://www.mylib.com/";
+    license = "GPL2";
+    maintainers = with stdenv.lib.maintainers; [qknight];
+  };
+}
+

c-programs/mylib/Makefile

@@ -0,0 +1,9 @@
+all :
+	g++ -c mylib.cpp -o mylib.o
+	ar rvs libmylib.a mylib.o
+	g++ -shared -o libmylib.so -fPIC mylib.cpp
+
+install :
+	cp libmylib.a ${prefix}/lib
+	cp libmylib.so ${prefix}/lib
+	cp mylib.hpp ${prefix}/include

c-programs/mylib/mylib.cpp

@@ -0,0 +1,3 @@
+int mylib(int i) {
+	return i+42-23;
+}

c-programs/mylib/mylib.hpp

@@ -0,0 +1,2 @@
+int mylib(int i); 
+