The mi_default_callback() function
The mi_default_callback() function is the system-default callback for all callbacks in a client LIBMI application.
Syntax
void mi_default_callback(event_type, conn, event_data, user_data)
MI_EVENT_TYPE event_type;
MI_CONNECTION *conn;
void *event_data;
void *user_data;- event_type
- The event type that the system-default callback is to handle.
- conn
- A pointer to a connection descriptor established by a previous call to mi_open(), mi_server_connect(), or mi_server_reconnect().
- event_data
- A pointer to the event-specific structure for the callback.
- user_data
- is a pointer to the user-defined error structure. For the MI_LIB_DROPCONN error level of the MI_Client_Library_Error event, this argument A flag to indicate whether to attempt a reconnection. If user_data is set to zero, the client LIBMI library attempts to reconnect to the database server; otherwise, no attempt is made to reconnect.
| Valid in client LIBMI application? | Valid in user-defined routine? |
|---|---|
| Yes | No |
Usage
The mi_default_callback() function implements the system-default callback, which returns appropriate error and warning messages in response to client events. Client events include the MI_Client_Library_Error and MI_Exception events.
On UNIX™ or Linux™, the system-default callback sends the error or warning message to stderr.
On Windows™, the system-default callback displays the error or warning message in a Windows™ message box.
The client LIBMI library automatically calls the system-default
callback when a client event occurs and the client LIBMI application
has no callback registered for this event. A client LIBMI application
can explicitly call mi_default_callback(). For
example, an application can register a special callback within a specific
function and then re-register mi_default_callback() after
the function completes to return to default behavior.
Important: When a client LIBMI application connects to a database
server, the mi_default_callback() function does
not report some warnings. The SQLSTATE values for these warnings
begin with
01I.To override the default behavior of the system-default callback, the client application can register a callback that handles the client event with the mi_default_callback() function.
Return values
None.