The progressCallBack method is an example of a user callback method for the progressHandler method. Here the method name of progressCallBack is used, because it is the default method name if the programmer does not specify his own name in the progressHandler method. Any method name can be used by specifying it as the second argument to the progressHandler method.

The progressHandler callback is invoked periodically after a number of virtual machine code instructions are evaluated. This number is specified by the second argument to the progressHandler method.

Note: there is no progressCallBack method in any ooSQLite class. This method is just used to illustrate how to define a user callback method to be used as a progress handler.

Arguments: The single argument sent to the callback method is:
userData [required] The user data object specified by the programmer as the fourth argument to theprogressHandlermethod. If the programmer did not specify a user data argument, this will be the.nilobject.
Return value: The programmer must return a whole number value from the callback. If the progress handler returns non-zero, the SQLite operation is interrupted. If 0 is returned the operation continues.
Remarks; The progress handler must not do anything that will modify the database connection that invoked the progress handler. Note that both instantiating a new The ooSQLiteStmt Class and the step method modify their database connections.
Details: The implementation of aprogressHandlercallback method is is discussed on the SQLite sqlite3_progress_handler page.