IupGetClassCallbacks
Returns the names of all registered callbacks of a class.
Parameters/Return
int IupGetClassCallbacks(const char* classname, char** names, int max_n);classname: name of the class
names: table receiving the names. Only the list of names needs
to be allocated. Each name will point to an internal string.
max_n: maximum number of names the table can
receive.
Returns: the actual number of names loaded to the table or -1 (nil) if class not found. If names==NULL or max_n==0 or -1 then returns the maximum number of names.