Informix DataBlade API Programmer's Manual DataBlade API Function Descriptions

The mi_unregister_callback() function unregisters a callback for an event type or for all event types.

mi_integer mi_unregister_callback(conn, event_type, cback_handle)

MI_CONNECTION *conn;

MI_EVENT_TYPE event_type;

MI_CALLBACK_HANDLE *cback_handle;

conn	is either NULL or a pointer to the connection descriptor a previous call to mi_open(), mi_server_connect(), or mi_server_reconnect() established.
event_type	is the event type for the callback. For a list of valid event types, see Figure 10-1 on page 10-4.
cback_handle	is the callback handle that a previous call to mi_register_callback() returned.

Valid in Client LIBMI Application?	Valid in User-Defined Routine?
Yes	Yes

The mi_unregister_callback() function unregisters the callback that cback_handle identifies for the event that event_type specifies.

For a C UDR, conn must be NULL for the following event types:

• MI_EVENT_END_STMT
• MI_EVENT_END_XACT
• MI_EVENT_END_SESSION

For a client LIBMI application, you must provide a valid connection descriptor to mi_retrieve_callback() for callbacks that handle the following event types:

• MI_Exception
• MI_Xact_State_Change
• MI_Client_Library_Error

The mi_register_callback() function registers a callback. The database server automatically unregisters a callback when either of the following occurs:

• For a state-transition callback: an end-of-statement (MI_EVENT_END_STMT), end-of-transaction (MI_EVENT_END_XACT), or end-of-session (MI_EVENT_END_SESSION) event occurs and the associated callback completes.
• The associated connection is closed (either the UDR exits or the mi_close() function executes)

Use the mi_unregister_callback() function to explicitly unregister a callback so that the database server does not invoke it when the event_type event occurs.

See the description of the mi_register_callback() function.

For a description of how to register and unregister a callback, see Registering a Callback.