From 5e779dca6f93b2b0da39c0253e5565d3e8571465 Mon Sep 17 00:00:00 2001
From: Robin Mueller <muellerr@irs.uni-stuttgart.de>
Date: Wed, 5 Oct 2022 11:03:55 +0200
Subject: [PATCH] 01 ws ipc

---
 README.md                        |  1 +
 ws-ipc/ipc-solutions/main-01.cpp | 36 ++++++++++++++++++++++++++++++++
 ws-tasks/README.md               | 19 ++++++++++++-----
 3 files changed, 51 insertions(+), 5 deletions(-)
 create mode 100644 ws-ipc/ipc-solutions/main-01.cpp

diff --git a/README.md b/README.md
index 46bdad2..9abc441 100644
--- a/README.md
+++ b/README.md
@@ -54,6 +54,7 @@ It is recommended to have a basic understanding of C++ basics and object-oriente
 in general before doing this workshop. There are various books and online resources available to
 learn this.
 
+All tasks are done in the `main.cpp` of this project and are located in subfolders.
 In general, it is recommended to start with the `ws-tasks` workshop and then move to the
 `ws-objects` workshop.
 
diff --git a/ws-ipc/ipc-solutions/main-01.cpp b/ws-ipc/ipc-solutions/main-01.cpp
new file mode 100644
index 0000000..86c3960
--- /dev/null
+++ b/ws-ipc/ipc-solutions/main-01.cpp
@@ -0,0 +1,36 @@
+#include <iostream>
+#include <thread>
+#include <mutex>
+
+using namespace std;
+
+std::mutex SHARED_LOCK;
+static uint32_t SHARED_COUNTER = 0;
+
+void task0() {
+    using namespace std::chrono_literals;
+    while (true) {
+        SHARED_LOCK.lock();
+        cout << "Task0: Shared counter after increment" << ++SHARED_COUNTER << endl;    
+        SHARED_LOCK.unlock();
+        this_thread::sleep_for(1000ms);
+    }
+}
+
+void task1() {
+    using namespace std::chrono_literals;
+    while(true) {
+        {
+            std::lock_guard lg(SHARED_LOCK);
+            cout << "Task1: Shared counter after increment" << ++SHARED_COUNTER << endl;    
+        }
+        this_thread::sleep_for(1000ms);
+    }
+}
+
+int main() {
+    std::thread t0(task0);
+    std::thread t1(task1);
+    t0.join();
+    t1.join();
+}
diff --git a/ws-tasks/README.md b/ws-tasks/README.md
index 2da331f..a297bbe 100644
--- a/ws-tasks/README.md
+++ b/ws-tasks/README.md
@@ -1,5 +1,9 @@
 # Threads and Tasks
 
+This workshop is split into 4 subtasks which are done in the `main.cpp` of this
+project.
+
+## Background Information
 A satellite is a complex system which usually has a lot of tasks which need to be done
 simulatenously by a dedicated On-Board Computer (OBC). This can include for example:
 
@@ -36,10 +40,12 @@ string every second: "Hello World".
 ## 2. Changing to the concept of executable objects
 
 The goal of this task is to convert the code from task 1 so the `std::thread` API takes an
-executable object to move to a more object oriented task approach. The printout of the thread
-should remain the same. The executable objects should be named `MyExecutableObject`. It contains
-one function called `periodicOperation` which performs the printout, and a static function which
-takes the `MyExecutableObject` itself by reference and executes it in a permanent loop.
+executable object by reference to move to a more object oriented task approach.
+
+The printout of the thread should remain the same. The executable objects should be named
+`MyExecutableObject`. It contains one function called `periodicOperation` which performs the 
+printout, and a static function which takes the `MyExecutableObject` itself by reference and
+executes it in a permanent loop.
 
 The executable object should be passed into the `std::thread` directly.
 
@@ -59,7 +65,10 @@ The executable object should be passed into the `std::thread` directly.
   4. Implement `executeTask`. This function uses the passed object and performs the scheduling
      specific part by calling `self.performOperation` in a permanent loop with a delay between
      calls. You can hardcode the delay to 1000ms for the first implementation.
-  5. Add a constructor to `MyExecutableObject` which expects a millisecond delay
+  5. Change your `std::thread` calls in the main. You can pass the new `executeTask` function
+     as the executable unit. The second argument should be an instance of the executable object
+     itself. You might need the `std::reference_wrapper` to pass it as a reference.
+  6. Add a constructor to `MyExecutableObject` which expects a millisecond delay
      as an `uint32_t` and cache it as a member variable. Then use this member
      variable in the `executeTask` implementation to make the task frequency configurable via the
      constructor (ctor) parameter.