#include <db_cxx.h> int DbEnv::cdsgroup_begin(DbTxn **tid);
         The DbEnv::cdsgroup_begin() method allocates a locker ID in an
         environment configured for Berkeley DB Concurrent Data Store
         applications.  It copies a pointer to a 
         DbTxn  that uniquely identifies
         the locker ID into the memory to which tid refers.  
         Calling the 
         DbTxn::commit()  method will
         discard the allocated locker ID.
    
See Berkeley DB Concurrent Data Store applications for more information about when this is required.
         The DbEnv::cdsgroup_begin() method may be called at any time during
         the life of the application.
    
         The DbEnv::cdsgroup_begin() 
            
            
                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::cdsgroup_begin() 
            
            
                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: