C++ ios_base Library - event


The C++ function ios_base::event is used as the first parameter in functions registered with ios_base::register_callback. This argument identifies the type of event that triggered the function call.


Following is the declaration for ios_base::event.

enum event;

Values of ios_event should be like this −

value event triggered
copyfmt_event on a call to ios::copyfmt (at the moment where all format flags have been copied, but before the exception mask is)
erase_event on a call to the stream destructor (also called at the beginning of ios::copyfmt).
imbue_event on a call to ios_base::imbue (just before the function returns).

This member enum type is defined within ios_base as −

enum event { erase_event, imbue_event, copyfmt_event };