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## Class named_condition

boost::interprocess::named_condition

## Synopsis

    // In header: <boost/interprocess/sync/named_condition.hpp>

    class named_condition {
    public:

      // public member functions
      named_condition(create_only_t, const char *,
                      const permissions & = permissions());
      named_condition(open_or_create_t, const char *,
                      const permissions & = permissions());
      named_condition(open_only_t, const char *);
      named_condition(create_only_t, const wchar_t *,
                      const permissions & = permissions());
      named_condition(open_or_create_t, const wchar_t *,
                      const permissions & = permissions());
      named_condition(open_only_t, const wchar_t *);
      ~named_condition();
      void notify_one();
      void notify_all();
      template<typename L> void wait(L &);
      template<typename L, typename Pr> void wait(L &, Pr);
      template<typename L, typename TimePoint>
        bool timed_wait(L &, const TimePoint &);
      template<typename L, typename TimePoint, typename Pr>
        bool timed_wait(L &, const TimePoint &, Pr);
      template<typename L, typename TimePoint>
        cv_status wait_until(L &, const TimePoint &);
      template<typename L, typename TimePoint, typename Pr>
        bool wait_until(L &, const TimePoint &, Pr);
      template<typename L, typename Duration>
        cv_status wait_for(L &, const Duration &);
      template<typename L, typename Duration, typename Pr>
        bool wait_for(L &, const Duration &, Pr);

      // public static functions
      static bool remove(const char *);
      static bool remove(const wchar_t *);
    };

## Description

A global condition variable that can be created by name. This condition variable is designed to work with named_mutex and can't be placed in shared memory or memory mapped files.

### `named_condition` public member functions

1.     named_condition(create_only_t, const char * name,
                       const permissions & perm = permissions());

   Creates a global condition with a name. If the condition can't be created throws interprocess_exception

2.     named_condition(open_or_create_t, const char * name,
                       const permissions & perm = permissions());

   Opens or creates a global condition with a name. If the condition is created, this call is equivalent to named_condition(create_only_t, ... ) If the condition is already created, this call is equivalent named_condition(open_only_t, ... ) Does not throw

3.     named_condition(open_only_t, const char * name);

   Opens a global condition with a name if that condition is previously created. If it is not previously created this function throws interprocess_exception.

4.     named_condition(create_only_t, const wchar_t * name,
                       const permissions & perm = permissions());

   Opens a global condition with a name if that condition is previously created. If it is not previously created this function throws interprocess_exception.

   Creates a global condition with a name. If the condition can't be created throws interprocess_exception

   Note: This function is only available on operating systems with native wchar_t APIs (e.g. Windows).

5.     named_condition(open_or_create_t, const wchar_t * name,
                       const permissions & perm = permissions());

   Opens or creates a global condition with a name. If the condition is created, this call is equivalent to named_condition(create_only_t, ... ) If the condition is already created, this call is equivalent named_condition(open_only_t, ... ) Does not throw

   Note: This function is only available on operating systems with native wchar_t APIs (e.g. Windows).

6.     named_condition(open_only_t, const wchar_t * name);

   Opens a global condition with a name if that condition is previously created. If it is not previously created this function throws interprocess_exception.

   Note: This function is only available on operating systems with native wchar_t APIs (e.g. Windows).

7.     ~named_condition();

   Destroys *this and indicates that the calling process is finished using the resource. The destructor function will deallocate any system resources allocated by the system for use by this process for this resource. The resource can still be opened again calling the open constructor overload. To erase the resource from the system use remove().

8.     void notify_one();

   If there is a thread waiting on this, change that thread's state to ready. Otherwise there is no effect.<zwj></zwj>/

9.     void notify_all();

   Change the state of all threads waiting on *this to ready. If there are no waiting threads, notify_all() has no effect.

10.     template<typename L> void wait(L & lock);

    Releases the lock on the named_mutex object associated with lock, blocks the current thread of execution until readied by a call to this->notify_one() or this->notify_all(), and then reacquires the lock.

11.     template<typename L, typename Pr> void wait(L & lock, Pr pred);

    The same as: while (!pred()) wait(lock)

12.     template<typename L, typename TimePoint>
          bool timed_wait(L & lock, const TimePoint & abs_time);

    Releases the lock on the named_mutex object associated with lock, blocks the current thread of execution until readied by a call to this->notify_one() or this->notify_all(), or until time abs_time is reached, and then reacquires the lock. Returns: false if time abs_time is reached, otherwise true.

13.     template<typename L, typename TimePoint, typename Pr>
          bool timed_wait(L & lock, const TimePoint & abs_time, Pr pred);

    The same as: while (!pred()) { if (!timed_wait(lock, abs_time)) return pred(); } return true;

14.     template<typename L, typename TimePoint>
          cv_status wait_until(L & lock, const TimePoint & abs_time);

    Same as `timed_wait`, but this function is modeled after the standard library interface.

15.     template<typename L, typename TimePoint, typename Pr>
          bool wait_until(L & lock, const TimePoint & abs_time, Pr pred);

    Same as `timed_wait`, but this function is modeled after the standard library interface.

16.     template<typename L, typename Duration>
          cv_status wait_for(L & lock, const Duration & dur);

    Same as `timed_wait`, but this function is modeled after the standard library interface and uses relative timeouts.

17.     template<typename L, typename Duration, typename Pr>
          bool wait_for(L & lock, const Duration & dur, Pr pred);

    Same as `timed_wait`, but this function is modeled after the standard library interface and uses relative timeouts

### `named_condition` public static functions

1.     static bool remove(const char * name);

   Erases a named condition from the system. Returns false on error. Never throws.

2.     static bool remove(const wchar_t * name);

   Erases a named condition from the system. Returns false on error. Never throws.

   Note: This function is only available on operating systems with native wchar_t APIs (e.g. Windows).