Events
IUP is a graphic-interface library, so most of the time it waits for an event to occur, such as a button click or a mouse leaving a window. The user can inform IUP that he/she wishes callbacks to be called, informing that en event has taken place. For further information on callbacks, see Guide / Events.
Attention: in a callback if one of the parameters is a string, this string may be modified during the callback if another IUP function (such as IupGetAttribute) is called.