cpg_model_initialize(3)

1CPG_MODEL_INITIALIZCEo(r3o)sync Cluster Engine Programmer's MCaPnGu_aMlODEL_INITIALIZE(3)
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NAME

6       cpg_model_initialize - Create a new connection to the CPG service
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SYNOPSIS

9       #include <corosync/cpg.h>
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11       cs_error_t   cpg_model_initialize(cpg_handle_t   *handle,   cpg_model_t
12       model, cpg_model_data_t *model_data, void *context);
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14

DESCRIPTION

16       The cpg_model_initialize function is used to initialize a connection to
17       the closed process groups API.
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19       Each  application  may  have  several connections to the CPG API.  Each
20       application uses the handle argument to uniquely identify  the  connec‐
21       tion.   The  handle  argument  is  then used in other function calls to
22       identify the connection to be used for communication with the CPG  ser‐
23       vice.
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25       Argument model is used to explicitly choose set of callbacks and inter‐
26       nal parameters. Currently only model CPG_MODEL_V1 is defined.
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28       Callbacks and internal parameters are passed  by  model_data  argument.
29       This is casted pointer (idea is similar as in sockaddr function) to one
30       of  structures  corresponding   to   chosen   model.   Currently   only
31       cpg_model_v1_data_t is needed.
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MODEL_V1

34       The  MODEL_V1  is backwards compatible with original callbacks initial‐
35       ized  by  cpg_initialize  but  new  callback  cpg_totem_confchg_fn   is
36       defined.
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38       Every  time  an  CPG  event  occurs within the joined group, one of the
39       callbacks specified by the argument callbacks is called.  The  callback
40       functions are described by the following type definitions:
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42              typedef void (*cpg_deliver_fn_t) (
43                      cpg_handle_t handle,
44                      const struct cpg_name *group_name,
45                      uint32_t nodeid,
46                      uint32_t pid,
47                      const void *msg,
48                      size_t msg_len);
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50
51              typedef void (*cpg_confchg_fn_t) (
52                      cpg_handle_t handle,
53                      const struct cpg_name *group_name,
54                      const struct cpg_address *member_list, size_t member_list_entries,
55                      const struct cpg_address *left_list, size_t left_list_entries,
56                      const struct cpg_address *joined_list, size_t joined_list_entries);
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58
59              typedef void (*cpg_totem_confchg_fn_t) (
60                      cpg_handle_t handle,
61                      struct cpg_ring_id ring_id,
62                      uint32_t member_list_entries,
63                      const uint32_t *member_list);
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65       The cpg_model_v1_data_t structure is defined as:
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67              typedef struct {
68                      cpg_model_t model;
69                      cpg_deliver_fn_t cpg_deliver_fn;
70                      cpg_confchg_fn_t cpg_confchg_fn;
71                      cpg_totem_confchg_fn_t cpg_totem_confchg_fn;
72              unsigned int flags;
73              } cpg_model_v1_data_t;
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75       When  a configuration change occurs or a message is to be delivered one
76       of the callbacks is called from the cpg_dispatch() function.  If a con‐
77       figuration change occurs, cpg_confchg_fn is called.  If a delivery of a
78       message occurs, cpg_deliver_fn is called.  When totem membership change
79       occurs,     cpg_totem_confchg_fn     is     called.    You    can    OR
80       CPG_MODEL_V1_DELIVER_INITIAL_TOTEM_CONF constant to flags to get  call‐
81       back after first confchg event.
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83       The cpg_address structure is defined
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85              struct cpg_address {
86                      unsigned int nodeid;
87                      unsigned int pid;
88                      unsigned int reason;
89              };
90
91       where  nodeid is a 32 bit unique node identifier, pid is the process ID
92       of the process that has joined/left the group or sent the message,  and
93       reason  is  an  integer  code  indicating  why the node joined/left the
94       group.
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96              CPG_REASON_JOIN     - the process joined a group using cpg_join().
97              CPG_REASON_LEAVE    - the process left a group using cpg_leave()
98              CPG_REASON_NODEDOWN - the process left a group because the node left the cluster.
99              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
100              CPG_REASON_PROCDOWN - the process left a group without calling cpg_leave()
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102       The cpg_ring_id structure is defined
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104              struct cpg_ring_id {
105                      uint32_t nodeid;
106                      uint64_t seq;
107              };
108
109       where nodeid is if of node of current Totem leader and seq is  increas‐
110       ing number.
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RETURN VALUE

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

118       The errors are undocumented.
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NAME

SYNOPSIS

DESCRIPTION

MODEL_V1

RETURN VALUE

ERRORS

SEE ALSO