#include <db_cxx.h> int DbEnv::set_lk_max_locks(u_int32_t max);
Set the maximum number of locks supported by the Berkeley DB environment. This value is used by DbEnv::open() to estimate how much space to allocate for various lock-table data structures. The default value is 1000 locks. For specific information on configuring the size of the lock subsystem, see Configuring locking: sizing the system.
The database environment's maximum number of locks may also be configured using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_lk_max_locks", one or more whitespace characters, and the number of locks. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.
         The DbEnv::set_lk_max_locks() method configures a database
         environment, not only operations performed using the specified 
         DbEnv  handle.
    
         The DbEnv::set_lk_max_locks() method may not be called after the
         DbEnv::open()  method is
         called. If the database environment already exists when 
         DbEnv::open()  is called, the
         information specified to DbEnv::set_lk_max_locks() will be ignored.
    
         The DbEnv::set_lk_max_locks() 
            
            
                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.
            
        
    
                         The DbEnv::set_lk_max_locks() 
            
            
                method may fail and throw a DbException 
                exception, encapsulating one of the following non-zero errors, or return one
                of the following non-zero errors:
            
        
                    
If the method was called after DbEnv::open() was called; or if an invalid flag value or parameter was specified.