Method
GtkExpressionwatch
Declaration [src]
GtkExpressionWatch*
gtk_expression_watch (
  GtkExpression* self,
  GObject* this_,
  GtkExpressionNotify notify,
  gpointer user_data,
  GDestroyNotify user_destroy
)
Description [src]
Watch the given expression for changes.
The notify function will be called whenever the evaluation of self
may have changed.
GTK cannot guarantee that the evaluation did indeed change when the notify
gets invoked, but it guarantees the opposite: When it did in fact change, the notify will be invoked.
Parameters
- this_
- 
            Type: GObjectThe thisargument to watch.The argument can be NULL.The data is owned by the caller of the method. 
- notify
- 
            Type: GtkExpressionNotifyCallback to invoke when the expression changes. 
- user_data
- 
            Type: gpointerUser data to pass to the notifycallback.The argument can be NULL.The data is owned by the caller of the method. 
- user_destroy
- 
            Type: GDestroyNotifyDestroy notify for user_data.
Return value
Type: GtkExpressionWatch
The newly installed watch. Note that the only
  reference held to the watch will be released when the watch is unwatched
  which can happen automatically, and not just via
  gtk_expression_watch_unwatch(). You should call gtk_expression_watch_ref()
  if you want to keep the watch around.
| The returned data is owned by the instance. |