OBJECT HEADERS
--------------

haddr_t
H5O_new (hdf5_file_t *f, intn nrefs, size_t size_hint)

	Creates a new empty object header and returns its address.
	The SIZE_HINT is the initial size of the data portion of the
	object header and NREFS is the number of symbol table entries
	that reference this object header (normally one).

	If SIZE_HINT is too small, then at least some default amount
	of space is allocated for the object header.

intn				        /*num remaining links		*/
H5O_link (hdf5_file_t *f,		/*file containing header	*/
	  haddr_t addr,			/*header file address		*/
	  intn adjust)			/*link adjustment amount	*/


size_t
H5O_sizeof (hdf5_file_t *f,		/*file containing header	*/
	    haddr_t addr,		/*header file address		*/
            H5O_class_t *type,		/*message type or H5O_ANY	*/
	    intn sequence)		/*sequence number, usually zero	*/
		
	Returns the size of a particular instance of a message in an
	object header.  When an object header has more than one
	instance of a particular message type, then SEQUENCE indicates
	which instance to return.

void *
H5O_read (hdf5_file_t *f,		/*file containing header	*/
	  haddr_t addr,			/*header file address		*/
	  H5G_entry_t *ent,		/*optional symbol table entry	*/
	  H5O_class_t *type,		/*message type or H5O_ANY	*/
	  intn sequence,		/*sequence number, usually zero	*/
	  size_t size,			/*size of output message	*/
	  void *mesg)			/*output buffer			*/

	Reads a message from the object header into memory.

const void *
H5O_peek (hdf5_file_t *f,		/*file containing header	*/
          haddr_t addr,			/*header file address		*/
	  H5G_entry_t *ent,		/*optional symbol table entry	*/
	  H5O_class_t *type,		/*type of message or H5O_ANY	*/
	  intn sequence)		/*sequence number, usually zero	*/

haddr_t					/*new heap address		*/
H5O_modify (hdf5_file_t *f,		/*file containing header	*/
            haddr_t addr,		/*header file address		*/
	    H5G_entry_t *ent,		/*optional symbol table entry	*/
	    hbool_t *ent_modified,	/*entry modification flag	*/
	    H5O_class_t *type,		/*message type			*/
	    intn overwrite,		/*sequence number or -1		*/
	    void *mesg)			/*the message			*/