IupUser
Creates a user element in IUP, which is not associated to any interface element. It is used to map an external element to a IUP element. Its use is usually done by CPI elements, but you can use it to create an Ihadle* to store private attributes.
Creation
Ihandle* IupUser(void); [in C] [There is no equivalent in Lua] [There is no equivalent in LED]
Returns: the identifier of the created element, or NULL if an error occurs.