GtkButton::set_use_underline
void set_use_underline(bool
underline);
Use this method to set the use_underline
property of the button to the parameter underline.
If use_underline is true, an underscore
in the text of the button label indicates that the next character should be
underlined and used for the mnemonic accelerator key.
参照:
get_use_underline()