NAME

       cpg_model_initialize - Create a new connection to the CPG service

SYNOPSIS

       #include <corosync/cpg.h>

       cs_error_t  cpg_model_initialize(cpg_handle_t  *handle,  cpg_model_t model, cpg_model_data_t *model_data,
       void *context);

DESCRIPTION

       The cpg_model_initialize function is used to initialize a connection to the closed process groups API.

       Each application may have several connections to the CPG 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 CPG service.

       Argument model is used to explicitly choose set of callbacks  and  internal  parameters.  Currently  only
       model CPG_MODEL_V1 is defined.

       Callbacks  and  internal  parameters  are  passed by model_data argument. This is casted pointer (idea is
       similar as in sockaddr function) to one of structures  corresponding  to  chosen  model.  Currently  only
       cpg_model_v1_data_t is needed.

MODEL_V1

       The  MODEL_V1  is  backwards  compatible  with  original  callbacks initialized by cpg_initialize but new
       callback cpg_totem_confchg_fn is defined.

       Every time an CPG event occurs within the joined group, one of the callbacks specified  by  the  argument
       callbacks is called.  The callback functions are described by the following type definitions:

              typedef void (*cpg_deliver_fn_t) (
                      cpg_handle_t handle,
                      const struct cpg_name *group_name,
                      uint32_t nodeid,
                      uint32_t pid,
                      const void *msg,
                      size_t msg_len);

              typedef void (*cpg_confchg_fn_t) (
                      cpg_handle_t handle,
                      const struct cpg_name *group_name,
                      const struct cpg_address *member_list, size_t member_list_entries,
                      const struct cpg_address *left_list, size_t left_list_entries,
                      const struct cpg_address *joined_list, size_t joined_list_entries);

              typedef void (*cpg_totem_confchg_fn_t) (
                      cpg_handle_t handle,
                      struct cpg_ring_id ring_id,
                      uint32_t member_list_entries,
                      const uint32_t *member_list);

       The cpg_model_v1_data_t structure is defined as:

              typedef struct {
                      cpg_model_t model;
                      cpg_deliver_fn_t cpg_deliver_fn;
                      cpg_confchg_fn_t cpg_confchg_fn;
                      cpg_totem_confchg_fn_t cpg_totem_confchg_fn;
              unsigned int flags;
              } cpg_model_v1_data_t;

       When  a  configuration  change occurs or a message is to be delivered one of the callbacks is called from
       the cpg_dispatch() function.  If a configuration change occurs, cpg_confchg_fn is called.  If a  delivery
       of a message occurs, cpg_deliver_fn is called.  When totem membership change occurs, cpg_totem_confchg_fn
       is called. You can OR CPG_MODEL_V1_DELIVER_INITIAL_TOTEM_CONF constant to flags  to  get  callback  after
       first confchg event.

       The cpg_address structure is defined

              struct cpg_address {
                      unsigned int nodeid;
                      unsigned int pid;
                      unsigned int reason;
              };

       where  nodeid  is  a  32  bit  unique  node  identifier,  pid  is  the process ID of the process that has
       joined/left the group or sent the message, and  reason  is  an  integer  code  indicating  why  the  node
       joined/left the group (this value is not set for the member_list items).

              CPG_REASON_JOIN      - the process joined a group using cpg_join().
              CPG_REASON_LEAVE     - the process left a group using cpg_leave()
              CPG_REASON_NODEDOWN  - the process left a group because the node left the cluster.
              CPG_REASON_NODEUP    - the process joined a group because it was already a member of a group on a node that has just joined the cluster
              CPG_REASON_PROCDOWN  - the process left a group without calling cpg_leave()
              CPG_REASON_UNDEFINED - a special value used for the member_list items

       The cpg_ring_id structure is defined

              struct cpg_ring_id {
                      uint32_t nodeid;
                      uint64_t seq;
              };

       where nodeid is if of node of current Totem leader and seq is increasing number.

RETURN VALUE

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

ERRORS

       The errors are undocumented.

SEE ALSO

       cpg_overview(3),   cpg_initialize(3),   cpg_finalize(3),   cpg_fd_get(3),  cpg_dispatch(3),  cpg_join(3),
       cpg_leave(3),     cpg_mcast_joined(3),     cpg_membership_get(3)     cpg_zcb_alloc(3)     cpg_zcb_free(3)
       cpg_zcb_mcast_joined(3) cpg_context_get(3) cpg_context_set(3) cpg_local_get(3) cpg_model_initialize(3)

       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