NAME

       quorum_model_initialize - Create a new connection to the Quorum service

SYNOPSIS

       #include <corosync/quorum.h>

       cs_error_t    quorum_model_initialize(quorum_handle_t   *handle,   quorum_model_t   model,
       quorum_model_data_t *model_data, uint32_t *quorum_type,void *context);

DESCRIPTION

       The quorum_model_initialize function is an enhanced way to initialize a connection to  the
       quorum API.

       Each  application  may  have several connections to the quorum API.  Each application uses
       the handle argument to uniquely identify the connection.  The handle argument is then used
       in  other  function calls to identify the connection to be used for communication with the
       quorum service.

       The model is used to explicitly choose set of callbacks and internal parameters. Currently
       two  models  QUORUM_MODEL_V0 and QUORUM_MODEL_V1 are defined.  QUORUM_MODEL_V0 exists only
       for compatibility reasons with quorum_initialize(3) function and it is not recommended  to
       be used as an argument for quorum_model_initialize(3).

       The Following description is focused only on QUORUM_MODEL_V1 model.

       Every  time the voting configuration changes (eg a node joins or leave the cluster) or the
       quorum status changes the quorum callback is called.   The  quorum  callback  function  is
       described by the following type definitions:

       typedef void (*quorum_v1_quorum_notification_fn_t) (
               quorum_handle_t handle,
               uint32_t quorate,
               struct quorum_ring_id ring_id,
               uint32_t member_list_entries,
               const uint32_t *member_list
       );

       Also  every  time  when  membership  configuration  changes  (eg a node joins or leave the
       cluster) the node list change callback is called before the  quorum  callback.   The  node
       list change callback function is described by the following type definitions:

       typedef void (*quorum_v1_nodelist_notification_fn_t) (
               quorum_handle_t handle,
               struct quorum_ring_id ring_id,
               uint32_t member_list_entries,
               const uint32_t *member_list,
               uint32_t joined_list_entries,
               const uint32_t *joined_list,
               uint32_t left_list_entries,
               const uint32_t *left_list
       );

       The model_data argument for QUORUM_MODEL_V1 is of the type:

       typedef struct {
               quorum_model_t model;
               quorum_v1_quorum_notification_fn_t quorum_notify_fn;
               quorum_v1_nodelist_notification_fn_t nodelist_notify_fn;
       } quorum_model_v1_data_t;

       It's  not  required (nor recommended) to set model field in the structure. It is also fine
       if only some of notification callbacks are used  (only  these  events  will  be  delivered
       then).

       The quorum_type argument is set to:

       #define QUORUM_FREE     0
       #define QUORUM_SET      1

       QUORUM_FREE value means that no quorum algorithm is loaded and that no callbacks will take
       place.

       QUORUM_SET value means that one quorum algorithm is configured  and  that  callbacks  will
       take place.

       The context argument sets context same way as quorum_context_set(3).

       When  a  configuration  change  occurs, the callback is called from the quorum_dispatch(3)
       function.

RETURN VALUE

       This call returns the CS_OK value if successful, otherwise an error is returned.

ERRORS

       CS_ERR_TRY_AGAIN Resource temporarily unavailable

       CS_ERR_INVALID_PARAM Invalid argument

       CS_ERR_ACCESS Permission denied

       CS_ERR_LIBRARY The connection failed

       CS_ERR_INTERRUPT System call interrupted by a signal

       CS_ERR_NOT_SUPPORTED The requested protocol/functionality not supported

       CS_ERR_MESSAGE_ERROR Incorrect auth message received

       CS_ERR_NO_MEMORY Not enough memory to complete the requested task

SEE ALSO

       quorum_overview(3),   quorum_initialize(3),   quorum_finalize(3),    quorum_getquorate(3),
       quorum_trackstart(3),     quorum_trackstop(3),    quorum_fd_get(3),    quorum_dispatch(3),
       quorum_context_set(3), quorum_context_get(3)