/usr/include/bobcat/semaphore is in libbobcat-dev 4.08.02-2build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 | #ifndef INCLUDED_BOBCAT_SEMAPHORE_
#define INCLUDED_BOBCAT_SEMAPHORE_
#include <mutex>
#include <condition_variable>
#include <chrono>
namespace FBB
{
class Semaphore
{
    mutable std::mutex d_mutex;
    std::condition_variable d_condition;
    size_t d_nAvailable;
    public:
        Semaphore(size_t nAvailable);
        template <typename Fun, typename ...Params>
        bool wait(Fun fun, Params &&...args);        // wait # available
        void wait();        // wait # available
                                        
                            // wait for duration timeunits
        template <typename Rep, typename Period>
        std::cv_status wait_for(std::chrono::duration<Rep, Period> 
                                                            const &relTime);
                            // wait until abs. time has been reached
        template <typename Clock, typename Duration>  
        std::cv_status wait_until(std::chrono::time_point<Clock, Duration> 
                                                            const &absTime);
        void notify();      // notify a single waiting thread if initially 0
        void notify_all();  // notify_all # available, notify if initially 0
        void set(size_t available = 0);
        size_t size() const;
};
inline size_t  Semaphore::size() const
{
    return d_nAvailable;
}
template <typename Rep, typename Period>
std::cv_status Semaphore::wait_for(
                        std::chrono::duration<Rep, Period> const &relTime)
{
    std::unique_lock<std::mutex> lk(d_mutex);   // get the lock
    while (d_nAvailable == 0)
        if (d_condition.wait_for(lk, relTime) == std::cv_status::timeout)
            return std::cv_status::timeout;
    --d_nAvailable;
    return std::cv_status::no_timeout;
}
template <typename Clock, typename Duration>  // wait until abs. time
std::cv_status Semaphore::wait_until(std::chrono::time_point<Clock, Duration> 
                                     const &absTime) 
{
    std::unique_lock<std::mutex> lk(d_mutex);   // get the lock
    while (d_nAvailable == 0)
        if (d_condition.wait_until(lk, absTime) == std::cv_status::timeout)
            return std::cv_status::timeout;
    --d_nAvailable;
    return std::cv_status::no_timeout;
}
template <typename Fun, typename ...Params>
bool Semaphore::wait(Fun fun, Params &&...args)
{
    std::unique_lock<std::mutex> lk(d_mutex);   // get the lock
    while (d_nAvailable == 0)
    {
        d_condition.wait(lk);   // see 'wait.cc' 
                                                    // called on notifications
        if (not fun(std::forward<Params>(args)...))
            return false;
    }
    --d_nAvailable;              // dec. semaphore
    return true;
}
}   // FBB
#endif
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