Description GBinding is the representation of a binding between a property on a GObject instance (or source) and another property on another GObject instance (or target). Whenever the source property changes, the same value is applied to the target property; for instance, the following binding: will cause object2:property-b to be updated every time g_object_set() or the specific accessor changes the value of object1:property-a. It is possible to create a bidirectional binding between two properties of two GObject instances, so that if either property changes, the other is updated as well, for instance: will keep the two properties in sync. It is also possible to set a custom transformation function (in both directions, in case of a bidirectional binding) to apply a custom transformation from the source value to the target value before applying it; for instance, the following binding: will keep the value property of the two adjustments in sync; the celsius_to_fahrenheit function will be called whenever the adjustment1:value property changes and will transform the current value of the property before applying it to the adjustment2:value property; vice versa, the fahrenheit_to_celsius function will be called whenever the adjustment2:value property changes, and will transform the current value of the property before applying it to the adjustment1:value. Note that GBinding does not resolve cycles by itself; a cycle like might lead to an infinite loop. The loop, in this particular case, can be avoided if the objects emit the "notify" signal only if the value has effectively been changed. A binding is implemented using the "notify" signal, so it is susceptible to all the various ways of blocking a signal emission, like g_signal_stop_emission() or g_signal_handler_block(). A binding will be severed, and the resources it allocates freed, whenever either one of the GObject instances it refers to are finalized, or when the GBinding instance loses its last reference. GBinding is available since GObject 2.26