C# Example: Running threads with unsynchronized data access

Assume a simple situation with a single global variable of type string, one access function for writing and one access function for reading the value:

        // within class Program

        // Global string variable     
        static string g_info = "Initial value";

        // Sets g_info to the given value in an endless loop
        static void SetValue(string in_newValue)
        {
            do
            {
                g_info = "";
                for (int i = 0; i < in_newValue.Length; ++i)
                {
                    g_info += in_newValue[i];
                }
                // Remark: in contrast with C++ direct setting g_info = in_newValue
                // is atomic in C#
            }
            while (true);
        }

        // Reads current value of g_info and writes it to console
        static void GetValue()
        {
            do
            {
                Console.Write(g_info);

            } while (true);
        }

Within a multithreaded environment multiple threads may call the access functions:

            // Start 3 threads, 2 are changing the global string to different values
            // one is reading the current value and writes it to console
            System.Threading.Thread t1 = new System.Threading.Thread(() => SetValue("ABCDEFGHIJK"));
            System.Threading.Thread t2 = new System.Threading.Thread(() => SetValue("___________"));
            System.Threading.Thread t3 = new System.Threading.Thread(GetValue);
            t1.Start();
            t2.Start();
            t3.Start();

            // program will run forever
            // Hint: terminate program using Ctrl-C

Running the program leads to an output similar to C++ Example: Running threads with unsynchronized data access

Within source code the variable is set to one of the two values "ABCDEFGHIJK" and "___________". But because of the missing synchronization a random mix of the possible values can be observed.