An application can establish coordinated transaction connections by calling the SQLSetEnvAttr() function, or by setting the CONNECTTYPE and SYNCPOINT keywords in the DB2 CLI initialization file or in the connection string for SQLDriverConnect(). The initialization file is intended for existing applications that do not use the SQLSetConnectAttr() function. For information about the keywords, refer to "DB2 CLI/ODBC Configuration Keyword Listing".
An application cannot have a mixture of concurrent and coordinated connections, the type of the first connection will determine the type of all subsequent connections. SQLSetEnvAttr() will return an error if an application attempts to change the connect type while there is an active connection.