+GVariant *g_variant_new_uint64(uint64_t value);
+GVariant *g_variant_new_boolean(gboolean value);
+GVariant *g_variant_new_double(double value);
+GVariant *g_variant_new_string(char *value);
+GVariant *g_variant_new_tuple(GVariant *children[], unsigned long n_children);
+char *g_variant_get_type_string(GVariant *value);
+uint64_t g_variant_get_uint64(GVariant *value);
+gboolean g_variant_get_boolean(GVariant *value);
+double g_variant_get_double(GVariant *value);
+char *g_variant_get_string(GVariant *value, unsigned long *length);
+GVariant *g_variant_get_child_value(GVariant *value, unsigned long index);
+