Added a bit more explanations.

CppTimerCallback.h

@@ -4,6 +4,8 @@
 #include "CppTimer.h"
 #include <unistd.h>
 
+// Demo which creates a callback interface as the abstract class "Runnable".
+// This then allows to register a callback.
 
 class CppTimerCallback : public CppTimer {
 

CppTimerStdFuncCallback.h

@@ -5,6 +5,9 @@
 #include <unistd.h>
 #include <functional>
 
+// This is a demo how to create a callback with std::function which allows
+// calling methods in other classes by registering a lambda function!
+
 class CppTimerCallback : public CppTimer {
 
 public:

demo_stdfunccallback.cpp

@@ -3,6 +3,9 @@
 #include <unistd.h>
 #include <thread>
 
+// Demo which shows how to register a callback via a lambda function.
+// The method run() in the receiving classes below is called from the class CppTimerCallback.
+
 class ReceiverClass1 {
 public:
     void run() {