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## Class shared_memory_object

boost::interprocess::shared_memory_object

## Synopsis

    // In header: <boost/interprocess/shared_memory_object.hpp>

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

      // public member functions
      void swap(shared_memory_object &);
      void truncate(offset_t);
      const char * get_name() const;
      bool get_size(offset_t &) const;
      mode_t get_mode() const;
      mapping_handle_t get_mapping_handle() const;
      void priv_close();
      bool priv_open_or_create(unspecified, const char *, mode_t,
                               const permissions &);

      // public static functions
      static bool remove(const char *);
      file_handle_t m_handle;
      mode_t m_mode;
      std::string m_filename;
    };

## Description

A class that wraps a shared memory mapping that can be used to create mapped regions from the mapped files

### `shared_memory_object` public construct/copy/destruct

1.     shared_memory_object();

   @ //Non-copyable and non-assignable

   @

   Default constructor. Represents an empty shared_memory_object.

2.     shared_memory_object(create_only_t, const char * name, mode_t mode,
                            const permissions & perm = permissions());

   Creates a shared memory object with name "name" and mode "mode", with the access mode "mode" If the file previously exists, throws an error.

3.     shared_memory_object(open_or_create_t, const char * name, mode_t mode,
                            const permissions & perm = permissions());

   Tries to create a shared memory object with name "name" and mode "mode", with the access mode "mode". If the file previously exists, it tries to open it with mode "mode". Otherwise throws an error.

4.     shared_memory_object(open_only_t, const char * name, mode_t mode);

   Tries to open a shared memory object with name "name", with the access mode "mode". If the file does not previously exist, it throws an error.

5.     shared_memory_object(shared_memory_object && moved);

   Moves the ownership of "moved"'s shared memory object to *this. After the call, "moved" does not represent any shared memory object. Does not throw

6.     shared_memory_object& operator=(shared_memory_object && moved);

   Moves the ownership of "moved"'s shared memory to *this. After the call, "moved" does not represent any shared memory. Does not throw

7.     ~shared_memory_object();

   Destroys *this and indicates that the calling process is finished using the resource. All mapped regions are still valid after destruction. 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().

### `shared_memory_object` public member functions

1.     void swap(shared_memory_object & moved);

   Swaps the shared_memory_objects. Does not throw.

2.     void truncate(offset_t length);

   Sets the size of the shared memory mapping.

3.     const char * get_name() const;

   Returns the name of the shared memory object.

4.     bool get_size(offset_t & size) const;

   Returns true if the size of the shared memory object can be obtained and writes the size in the passed reference

5.     mode_t get_mode() const;

   Returns access mode.

6.     mapping_handle_t get_mapping_handle() const;

   Returns mapping handle. Never throws.

7.     void priv_close();

   @ private:

   Closes a previously opened file mapping. Never throws.

8.     bool priv_open_or_create(unspecified type, const char * filename, mode_t mode,
                                const permissions & perm);

   Closes a previously opened file mapping. Never throws.

### `shared_memory_object` public static functions

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

   Erases a shared memory object from the system. Returns false on error. Never throws