Declaration [src]

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.


this_ GObject

The this argument to watch.

 The argument can be NULL.
 The data is owned by the caller of the function.
notify GtkExpressionNotify

Callback to invoke when the expression changes.

user_data gpointer

User data to pass to the notify callback.

user_destroy GDestroyNotify

Destroy notify for user_data

Return value

Returns: 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 data is owned by the instance.