Gio.DBusProxy.set_cached_property

### Method

# Gio DBusProxyset_cached_property

since: 2.26

#### Declaration

    void
    g_dbus_proxy_set_cached_property (
      GDBusProxy* proxy,
      const gchar* property_name,
      GVariant* value
    )

#### Description

If `value` is not `NULL`, sets the cached value for the property with name `property_name` to the value in `value`.

If `value` is `NULL`, then the cached value is removed from the property cache.

If `proxy` has an expected interface (see `GDBusProxy:g-interface-info`) and `property_name` is referenced by it, then `value` is checked against the type of the property.

If the `value` `GVariant` is floating, it is consumed. This allows convenient ‘inline’ use of g_variant_new(), e.g.

     g_dbus_proxy_set_cached_property (proxy,
                                       "SomeProperty",
                                       g_variant_new ("(si)",
                                                     "A String",
                                                     42));

Normally you will not need to use this method since `proxy` is tracking changes using the `org.freedesktop.DBus.Properties.PropertiesChanged` D-Bus signal. However, for performance reasons an object may decide to not use this signal for some properties and instead use a proprietary out-of-band mechanism to transmit changes.

As a concrete example, consider an object with a property `ChatroomParticipants` which is an array of strings. Instead of transmitting the same (long) array every time the property changes, it is more efficient to only transmit the delta using e.g. signals `ChatroomParticipantJoined(String name)` and `ChatroomParticipantParted(String name)`.

Available since: 2.26

#### Parameters

`property_name`

  Type: `const gchar*`

  Property name.

  The data is owned by the caller of the method.
  The value is a NUL terminated UTF-8 string.

`value`

  Type: `GVariant`

  Value for the property or `NULL` to remove it from the cache.

  The argument can be `NULL`.
  The data is owned by the caller of the method.