# mco_HA_set_master_params

This function is called by the master (and a replica becoming master) to set the master HA runtime parameters.

### For an overview see page HA Applications

### Prototype

        void	mco_HA_set_master_params(	mco_db_h db,
                          mco_HA_master_params_t* params )

### Arguments

db | Database connection handle
params | HA master parameters defined in structure `mco_HA_master_params_t`

### Description

This function is called by the master to set the master HA runtime parameters. It is also called when a replica application must change its role to master. The role of the HA runtime is implicitly set to ‘standby’ when it calls``mco_HA_attach_master`()`, or to ‘master’ when it calls `mco_HA_attach_replica()`. ``mco_HA_set_master_params()`` is also used when it is necessary to set the HA mode to “shared commit” (see `mco_HA_trans_commit_synch()`)

### Return Codes

MCO_S_OK | The HA mode was set successfully
MCO_E_HA_NOT_INITIALIZED | The function mco_HA_start() must be called first
MCO_E_HA_MULTICAST_NOT_SUPP | Multicast not enabled.
MCO_E_HA_HOTSYNCH_NOT_SUPP | Hot-synch not enabled
MCO_E_HA_ASYNCH_NOT_SUPP | Asynchronous replication not enabled.
MCO_E_HA_MAXREPLICAS | Max number of replicas exceeded
MCO_E_HA_INVALID_PARAMETER | Shared commit not enabled.