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## Class named_mutex

boost::interprocess::named_mutex

## Synopsis

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

    class named_mutex {
    public:
      // construct/copy/destruct
      named_mutex(create_only_t, const char *,
                  const permissions & = permissions());
      named_mutex(open_or_create_t, const char *,
                  const permissions & = permissions());
      named_mutex(open_only_t, const char *);
      ~named_mutex();

      // public member functions
      void unlock();
      void lock();
      bool try_lock();
      bool timed_lock(const boost::posix_time::ptime &);

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

## Description

A mutex with a global name, so it can be found from different processes. This mutex can't be placed in shared memory, and each process should have it's own named_mutex.

### `named_mutex` public construct/copy/destruct

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

   Creates a global `interprocess_mutex` with a name. Throws `interprocess_exception` on error.

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

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

3.     named_mutex(open_only_t open_only, const char * name);

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

4.     ~named_mutex();

   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().

### `named_mutex` public member functions

1.     void unlock();

   Unlocks a previously locked `interprocess_mutex`.

2.     void lock();

   Locks `interprocess_mutex`, sleeps when `interprocess_mutex` is already locked. Throws `interprocess_exception` if a severe error is found

3.     bool try_lock();

   Tries to lock the `interprocess_mutex`, returns false when `interprocess_mutex` is already locked, returns true when success. Throws `interprocess_exception` if a severe error is found

4.     bool timed_lock(const boost::posix_time::ptime & abs_time);

   Tries to lock the `interprocess_mutex` until time abs_time, Returns false when timeout expires, returns true when locks. Throws `interprocess_exception` if a severe error is found

### `named_mutex` public static functions

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

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