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.TH CPG_JOIN 3 2004-08-31 "corosync Man Page" "Corosync Cluster Engine Programmer's Manual"
.SH NAME
cpg_join \- Joins one or more groups in the CPG library
.SH SYNOPSIS
.B #include <corosync/cpg.h>
.sp
.BI "int cpg_join(cpg_handle_t " handle ", struct cpg_name *" group ");
.SH DESCRIPTION
The
.B cpg_join
function is used to join one group.  When a group is joined, the
.B cpg_mcast_joined(3)
is called internally to multicast to the groups joined in the argument
.I handle.
The process will also get notifications of other processes joining
and leaving the group.
Messages that are sent to any of the groups joined to the parameter
.I handle
will be delivered by
.B cpg_dispatch(3).
.PP
This function may be only be called once for each handle. When a group has been joined
the process will start to receive callbacks relating to messages sent from members
of the group or notifications of processes joining or leaving the group.
.PP
Note that more than one process on each node can join a CPG group and
each will receive its own copy of any messages sent using
.I cpg_mcast_joined()
and its own confchg callback.
.PP

The argument
.I group
is used to specify the group to join.


The
.I groups
argument is of the type struct cpg_name which is defined by the structure:

.IP
.RS
.ne 18
.nf
.ta 4n 30n 33n
struct cpg_name {
        int length;
        char value[128];
};
.ta
.fi
.RE
.IP
.PP
.PP
.SH RETURN VALUE
This call returns the CS_OK value if successful, CS_ERR_INVALID_PARAM if the
handle is already joined to a group.
.PP
.SH ERRORS
Not all errors are documented.
.SH "SEE ALSO"
.BR cpg_overview (3),
.BR cpg_initialize (3),
.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)
.BR cpg_zcb_alloc (3)
.BR cpg_zcb_free (3)
.BR cpg_zcb_mcast_joined (3)
.BR cpg_context_get (3)
.BR cpg_context_set (3)
.BR cpg_local_get (3)

.PP
.PP

.B CS_ERR_TRY_AGAIN
Resource temporarily unavailable

.B CS_ERR_INVALID_PARAM
Invalid argument

.B CS_ERR_ACCESS
Permission denied

.B CS_ERR_LIBRARY
The connection failed

.B CS_ERR_INTERRUPT
System call interrupted by a signal

.B CS_ERR_NOT_SUPPORTED
The requested protocol/functionality not supported

.B CS_ERR_MESSAGE_ERROR
Incorrect auth message received

.B CS_ERR_NO_MEMORY
Not enough memory to complete the requested task