C++0x has no semaphores? How to synchronize threads?

by

You can easily build one from a mutex and a condition variable:

#include <mutex>
#include <condition_variable>

class semaphore {
    std::mutex mutex_;
    std::condition_variable condition_;
    unsigned long count_ = 0; // Initialized as locked.

public:
    void release() {
        std::lock_guard<decltype(mutex_)> lock(mutex_);
        ++count_;
        condition_.notify_one();
    }

    void acquire() {
        std::unique_lock<decltype(mutex_)> lock(mutex_);
        while(!count_) // Handle spurious wake-ups.
            condition_.wait(lock);
        --count_;
    }

    bool try_acquire() {
        std::lock_guard<decltype(mutex_)> lock(mutex_);
        if(count_) {
            --count_;
            return true;
        }
        return false;
    }
};

More Related Contents:

  1. Start thread with member function
  2. How do I terminate a thread in C++11?
  3. Concurrency: Atomic and volatile in C++11 memory model
  4. Passing object by reference to std::thread in C++11
  5. Why don’t compilers merge redundant std::atomic writes?
  6. Are C++ Reads and Writes of an int Atomic?
  7. std::thread pass by reference calls copy constructor
  8. How would you implement your own reader/writer lock in C++11?
  9. Mixing C++11 atomics and OpenMP
  10. How to set the stacksize with C++11 std::thread
  11. How to use std::async on a member function?
  12. How to make a multiple-read/single-write lock from more basic synchronization primitives?
  13. How to give priority to privileged thread in mutex locking?
  14. C++0x thread interruption
  15. What causes runtime error message: std::system_error – operation not permitted, including mult-threading? [duplicate]
  16. What is the difference between packaged_task and async
  17. std::thread is not a member of namespace std using Eclipse Kepler MinGW
  18. c++ work queues with blocking
  19. Waiting for multiple futures?
  20. What is different between join() and detach() for multi threading in C++?
  21. std::thread error (thread not member of std)
  22. MinGW error: ‘thread’ is not a member of ‘std’
  23. ReleaseSemaphore does not release the semaphore
  24. Double-Checked Lock Singleton in C++11
  25. I want to kill a std::thread using its thread object? [duplicate]
  26. thread safety of MPI send using threads created with std::async
  27. GCC std::thread not found in namespace std
  28. C++11 Implementation of Spinlock using header “
  29. About thread-safety of weak_ptr
  30. Why does this simple std::thread example not work?

Leave a Comment