#include <db.h> int DB_ENV->lock_id_free(DB_ENV *env, u_int32_t id);
         The DB_ENV->lock_id_free() method frees a locker ID allocated by the
         DB_ENV->lock_id()  method.
    
         The DB_ENV->lock_id_free() 
            
                  method returns a non-zero error value on failure and 0 on success.
            
            
        
    
                         The DB_ENV->lock_id_free() 
            
                 method may fail and return one of the following non-zero errors: