#include <db_cxx.h>
int
DbEnv::repmgr_msg_dispatch(
void (*msg_dispatch_fcn) (DbEnv *env, DbChannel *channel,
Dbt *request, u_int32_t nrequest,
u_int32_t cb_flags),
u_int32_t flags);
Sets the message dispatch function. This function is responsible for receiving messages sent from remote sites using either the DbChannel::send_msg() or DbChannel::send_request() methods. If the message received by this function was sent using the DbChannel::send_msg() method then no response is required. If the message was sent using the DbChannel::send_request() method, then this function must send a response using the DbChannel::send_msg() method.
For best results, the
DbEnv::repmgr_msg_dispatch() method should
be called before the Replication Manager has been started.
The DbEnv::repmgr_msg_dispatch()
method either returns a non-zero error value or throws an
exception that encapsulates a non-zero error value on
failure, and returns 0 on success.
This parameter is the application-specific function used to handle messages sent over Replication Manager message channels. It takes four parameters:
channel
Provides the DbChannel to be used to send a response back to the originator of the message. If the message was sent by the remote site using DbChannel::send_request() then this function should send a response back to the originator using the channel provided on this parameter. The message should be sent by calling DbChannel::send_msg() exactly once.
This channel is valid only during the current
invocation of the dispatch function; it is
destroyed when the dispatch function returns. The
application may not save a copy of the pointer and
use it later elsewhere. Methods that do not make
sense in the context of a message dispatch
function (such as
DbChannel::send_request()
and
DbChannel::close()
)
will be rejected with EINVAL.
request
Array of Dbts containing the message received from the remote site.
nrequest
Specifies the number of elements in the
request array.
cb_flags
This flag is
DB_REPMGR_NEED_RESPONSE if the
message requires a response. Otherwise, it is
0.
This function does not return a value. If the function encounters an error, you can reflect the error back to the originator of the message by formatting an error message of your own design into the response.
The DbEnv::repmgr_msg_dispatch()
method may fail and throw a DbException
exception, encapsulating one of the following non-zero errors, or return one
of the following non-zero errors: