Retrieves the icon name used for the icon, or %NULL if there is no icon or if the icon was set by some other method (e.g., by pixbuf, stock or gicon).
Icon position
Return: An icon name, or %NULL if no icon is set or if the icon wasn’t set from an icon name
2.16
See Implementation
Retrieves the icon name used for the icon, or %NULL if there is no icon or if the icon was set by some other method (e.g., by pixbuf, stock or gicon).