Disable ToolButtons

[Adrián Ortega <elfus0 1 gmail com>]

I'm making a text editor and I have some Gtk::ToolButtons on it. What 
I'm trying to do is to enable/disable them, e.g. when nothing has been 
typed on the text field the Save button is disabled, like grayed out.. I 
think, (not hidden) so when something is typed I want the Save 
Gtk::ToolButton to be enabled. I know this question might be silly but 
I've searching and I haven't found the answer in the reference.

What method can I use to enable/disable the buttons, but keeping them in 
the Tool bar so you can see them all the time?

Thanks for your help.