drd/tests/std_mutex: Add a unit test for std::mutex

drd/tests/std_mutex.cpp

@@ -0,0 +1,39 @@
+// See also https://bugs.kde.org/show_bug.cgi?id=416286
+
+#include <mutex>
+#include <iostream>
+#include <thread>
+#include <vector>
+
+class counter {
+public:
+  counter(): mutex() {}
+  void get() { std::unique_lock<std::mutex> lock(mutex); }
+
+private:
+  std::mutex mutex;
+};
+
+static counter& get_counter()
+{
+  static counter manager;
+  return manager;
+}
+
+static void do_work()
+{
+  get_counter().get();
+}
+
+int main()
+{
+  std::vector<std::thread> v;
+
+  for (int i = 0; i < 16; i++)
+    v.emplace_back([]{ do_work(); });
+
+  for (auto& t : v)
+    t.join();
+
+  std::cerr << "Done.\n";
+}