TipcConnGmdResend

Name

TipcConnGmdResend — resend all guaranteed messages after a delivery failure on a connection

Synopsis

T_BOOL TipcConnGmdResend(conn) 
T_IPC_CONN conn;

Arguments

conn — connection to resend messages on

Return Values

TRUE if the guaranteed messages were successfully resent on the connection, FALSE otherwise.

Diagnostics

If TipcConnGmdResend fails, it returns FALSE and sets the global SmartSockets error number to one of:

T_ERR_NULL_PTR — conn was null

any error number from TipcConnGmdFileCreate

Description

TipcConnGmdResend resends guaranteed messages after a delivery failure on a connection. TipcConnGmdResend reads all the messages from the GMD area and calls TipcConnMsgSend for each one to resend. The receiving processes automatically detect any redundant messages they have already processed. See TipcConnGmdFileCreate for more information on GMD areas.

When a process using GMD creates a connection, one of two scenarios is possible:

the process does not care about GMD information from a previous connection with the same GMD configuration and should thus call TipcConnGmdFileDelete to delete the old files

the process is recreating the connection after a network failure and should thus call TipcConnGmdResend to resend all previously sent messages that may have been lost when the connection was destroyed

If the connection does not have a GMD area open and there are existing GMD files on disk then TipcConnGmdResend calls TipcConnGmdFileCreate to open the existing GMD files.

Caution

TipcConnGmdResend should only be used when a connection is first created.

TipcConnGmdResend resends all messages with GMD, but does not explicitly flush the messages. See TipcConnGetAutoFlushSize for more information on message buffering.

Examples

This example creates a client connection to a server process, calls TipcConnGmdResend to resend any existing GMD files for the connection, then sends a NUMERIC_DATA message with guaranteed delivery to the server process:

T_IPC_CONN conn; 
T_IPC_MT mt; 
T_IPC_MSG msg; 
 
/* have to set the Unique_Subject option to use file-based GMD */ 
TutCommandParseStr("setopt unique_subject example_client"); 
 
conn = TipcConnCreateClient("tcp:_node:4242"); 
if (conn == NULL) { 
  return;  /* error */ 
}  
 
/* Resend any previously sent messages with GMD. Use TipcConnGmdFileDelete instead of 
TipcConnGmdResend here if you wish to delete the existing GMD files instead of resending any 
previously sent GMD messages. */ 
if (!TipcConnGmdResend(conn)) { 
  return;  /* error */ 
} 
 
mt = TipcMtLookupByNum(T_MT_NUMERIC_DATA); 
if (mt == NULL) { 
  return;  /* error */ 
}  
 
if (!TipcConnMsgWrite(conn, mt, 
                      T_IPC_PROP_DELIVERY_MODE, T_IPC_DELIVERY_ALL, 
                      T_IPC_FT_STR, "test_value", 
                      T_IPC_FT_REAL8, 10.0, 
                      NULL)) { 
  return;  /* error */ 
}