offtopic colons and gtk (;

[Andreas Leitner <leitner eiffel com>]

Hi,

I know that question is slightly off topic, but it would be nice if you
would not flame me for this, or even better give me an answer (:

I have found some colons (':') in the source code of GTK for which I
don't know what exactly they are therefore. For example GtkEditable is
defined as follows:
--
struct _GtkEditable
{
  GtkWidget widget;

  /*< public >*/
  guint      current_pos;

  guint      selection_start_pos;
  guint      selection_end_pos;
  guint      has_selection : 1;

  /*< private >*/
  guint      editable : 1;
  guint      visible : 1;
  GdkIC     *ic;
  GdkICAttr *ic_attr;
  
  gchar *clipboard_text;
};

--
What do the ": 1" after `editable', `visible' and 'has_selection' mean?
I know this is a C question, but I have never seen such a construct
before. Any help is greatly apprechiated.

many thanks in advance,
Andeas