#include <db_cxx.h> int Db::get_q_extentsize(u_int32_t *extentsizep);
         The Db::get_q_extentsize() method returns the number of pages in an
         extent. This value is used only for Queue databases and is set using the
         Db::set_q_extentsize()
         method.
    
         The Db::get_q_extentsize() method may be
         called only after the database has been opened.
    
         The Db::get_q_extentsize() 
            
            
                method either returns a non-zero error value or throws an
                exception that encapsulates a non-zero error value on
                failure, and returns 0 on success.