Thread Guards: The first one takes ownership over the thread, the second one only ensures exception-safe join.

thread_guard.hpp

#include <thread>
#include <utility>
#include <stdexcept>


// takes ownership of the thread
class scoped_thread {
  public:
    explicit scoped_thread(std::thread t_) : t(std::move(t_)) {
      if(!t.joinable()) throw std::logic_error{"no thread"};
    }
    ~scoped_thread() { t.join(); }

    scoped_thread(scoped_thread const&) = delete;
    scoped_thread& operator=(scoped_thread const&) = delete;

  private:
    std::thread t;
};


// only ensures exception safe join
class thread_guard {
  public:
    explicit thread_guard(std::thread& t_) : t(t_) {}
    ~thread_guard() { if(t.joinable()) t.join(); }

    thread_guard(thread_guard const&) = delete;
    thread_guard& operator=(thread_guard const&) = delete;

  private:
    std::thread& t;
};