GDBusMessageFilterFunction

Signature for function used in g_dbus_connection_add_filter().

A filter function is passed a #GDBusMessage and expected to return a #GDBusMessage too. Passive filter functions that don't modify the message can simply return the @message object: |[ static GDBusMessage * passive_filter (GDBusConnection *connection GDBusMessage *message, gboolean incoming, gpointer user_data) { /<!-- -->* inspect @message *<!-- -->/ return message; } ]| Filter functions that wants to drop a message can simply return %NULL: |[ static GDBusMessage * drop_filter (GDBusConnection *connection GDBusMessage *message, gboolean incoming, gpointer user_data) { if (should_drop_message) { g_object_unref (message); message = NULL; } return message; } ]| Finally, a filter function may modify a message by copying it: |[ static GDBusMessage * modifying_filter (GDBusConnection *connection GDBusMessage *message, gboolean incoming, gpointer user_data) { GDBusMessage *copy; GError *error;

error = NULL; copy = g_dbus_message_copy (message, &error); /<!-- -->* handle @error being is set *<!-- -->/ g_object_unref (message);

/<!-- -->* modify @copy *<!-- -->/

return copy; } ]| If the returned #GDBusMessage is different from @message and cannot be sent on @connection (it could use features, such as file descriptors, not compatible with @connection), then a warning is logged to <emphasis>standard error</emphasis>. Applications can check this ahead of time using g_dbus_message_to_blob() passing a #GDBusCapabilityFlags value obtained from @connection.

alias GDBusMessageFilterFunction = GDBusMessage* function(GDBusConnection* connection, GDBusMessage* message, int incoming, void* userData)

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Since

2.26