From 9039c956906cc8241d795759a5866f46d936f821 Mon Sep 17 00:00:00 2001
From: Alex Hirsch <w4rh4wk@bluephoenix.at>
Date: Thu, 19 Nov 2020 23:47:47 +0100
Subject: [PATCH] Exercises: Add plugin system task

---
 exercises/README.md         | 27 +++++++++++++++++++++++++++
 exercises/task16/plugin.hpp | 19 +++++++++++++++++++
 2 files changed, 46 insertions(+)
 create mode 100644 exercises/task16/plugin.hpp

diff --git a/exercises/README.md b/exercises/README.md
index 5143d71..bf058b5 100644
--- a/exercises/README.md
+++ b/exercises/README.md
@@ -224,3 +224,30 @@ Take your vector implementation from Task 14 and instantiate it with a big numbe
 
 Inspect the relationship between the number of unique instantiates and compile time.
 Furthermore, look at the compiled object file using `nm`.
+
+## Task 16
+
+In this task you have to create a rudimentary plugin system.
+
+You are given `plugin.hpp` which contains an interface for your plugins, as well as the function name of the constructor function and its type.
+Note that the constructor function returns an `std::unique_ptr<Plugin>`.
+
+- create an executable which *dynamically* loads plugins and executes their `run` member function
+- create two different plugins (`foo` and `bar`) showing off the plugin system
+
+It could look like this:
+
+    $ ./main ./libFoo.so
+    Creation of first plugin
+    Running the first plugin
+    Destruction of first plugin
+
+    $ ./main ./libFoo.so ./libBar.so
+    Creation of first plugin
+    Running the first plugin
+    Destruction of first plugin
+    Creation of second plugin
+    Running the second plugin
+    Destruction of second plugin
+
+*Hint:* Have a look at the related man-pages *dlopen(3)* and *dlsym(3)*.
diff --git a/exercises/task16/plugin.hpp b/exercises/task16/plugin.hpp
new file mode 100644
index 0000000..a0f75ca
--- /dev/null
+++ b/exercises/task16/plugin.hpp
@@ -0,0 +1,19 @@
+#ifndef PLUGIN_HPP
+#define PLUGIN_HPP
+
+#include <memory>
+
+/// Interface for plugins.
+class Plugin {
+  public:
+	virtual void run() = 0;
+	virtual ~Plugin(){};
+};
+
+/// Symbol of the plugin constructor function.
+const auto PLUGIN_CONSTRUCTOR = "create_plugin";
+
+/// Type of the plugin constructor function.
+using PLUGIN_CONSTRUCTOR_T = std::unique_ptr<Plugin> (*)();
+
+#endif // PLUGIN_HPP