corosync/man/cpg_initialize.3

.\"/*
.\" * Copyright (c) 2006 Red Hat, Inc.
.\" *
.\" * All rights reserved.
.\" *
.\" * Author: Patrick Caulfield <pcaulfie@redhat.com>
.\" *
.\" * This software licensed under BSD license, the text of which follows:
.\" * 
.\" * Redistribution and use in source and binary forms, with or without
.\" * modification, are permitted provided that the following conditions are met:
.\" *
.\" * - Redistributions of source code must retain the above copyright notice,
.\" *   this list of conditions and the following disclaimer.
.\" * - Redistributions in binary form must reproduce the above copyright notice,
.\" *   this list of conditions and the following disclaimer in the documentation
.\" *   and/or other materials provided with the distribution.
.\" * - Neither the name of the MontaVista Software, Inc. nor the names of its
.\" *   contributors may be used to endorse or promote products derived from this
.\" *   software without specific prior written permission.
.\" *
.\" * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
.\" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
.\" * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
.\" * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
.\" * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
.\" * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
.\" * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
.\" * THE POSSIBILITY OF SUCH DAMAGE.
.\" */
.TH CPG_INITIALIZE 3 2004-08-31 "openais Man Page" "Openais Programmer's Manual"
.SH NAME
cpg_initialize \- Create a new connection to the CPG service
.SH SYNOPSIS
.B #include <openais/cpg.h>
.sp
.BI "int cpg_initialize(cpg_handle_t *" handle ", cpg_callbacks_t *" callbacks ");
.SH DESCRIPTION
The
.B cpg_initialize
function is used to initialize a connection to the closed process groups API.
.PP
Each application may have several connections to the CPG API.  Each  application
uses the 
.I handle
argument to uniquely identify the connection.  The
.I handle
argument is then used in other function calls to identify the connection to be used
for communication with the CPG service.
.PP
Every time an CPG event occurs within the joined group, one of the callbacks specified by the argument
.I callbacks
is called.  The callback functions are described by the following type definitions:
.PP
.PP
.IP
.RS
.ne 18
.nf
.ta 4n 20n 32n

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


typedef void (*cpg_confchg_fn_t) (
        cpg_handle_t handle,
        struct cpg_name *group_name,
        struct cpg_address *member_list, int member_list_entries,
        struct cpg_address *left_list, int left_list_entries,
        struct cpg_address *joined_list, int joined_list_entries);
.ta
.fi
.RE
.IP
.PP
.PP
The
.I callbacks
argument is of the type:
.IP
.RS
.ne 18
.nf
.PP
typedef struct {
        cpg_deliver_fn_t cpg_deliver_fn;
        cpg_confchg_fn_t cpg_confchg_fn;
} cpg_callbacks_t;
.ta
.fi
.RE
.IP
.PP
When a configuration change occurs or a message is to be delivered one of the callbacks
is called from the
.B cpg_dispatch()
function.  If a configuration change occurs,
.I cpg_confchg_fn
is called.  If a delivery of a message occurs,
.I cpg_deliver_fn
is called.

The
.I cpg_address
structure is defined 
.IP
.RS
.ne 18
.nf
.PP
struct cpg_address {
        unsigned int nodeid;
        unsigned int pid;
        unsigned int reason;
};
.ta
.fi
.RE
.IP
.PP
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 join/left the group.
.PP
.IP
.RS
.ne 18
.nf
.PP
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()
.ta
.fi
.RE
.IP
.PP
.SH RETURN VALUE
This call returns the CPG_OK value if successful, otherwise an error is returned.
.PP
.SH ERRORS
The errors are undocumented.
.SH "SEE ALSO"
.BR cpg_overview (8),
.BR cpg_finalize (3),
.BR cpg_fd_get (3),
.BR cpg_dispatch (3),
.BR cpg_join (3),
.BR cpg_leave (3),
.BR cpg_mcast_joined (3),
.BR cpg_membership_get (3)
.PP