我目前尝试与 dbus 通信并有一个函数,该函数将返回array of struct(string, uint32, string, string, object path)
。我将结果存储在GVariant
并打印这个GVariant
显示那里有正确的结果值。
更具描述性:我尝试获取 Systemd 的 Logind Managers 的结果ListSessions
.
打印的输出是:
[('2', uint32 1000, 'nidhoegger', 'seat0', objectpath
'/org/freedesktop/login1/session/_32'), ('6', 1001, 'test', 'seat0',
'/org/freedesktop/login1/session/_36'), ('c2', 111, 'lightdm',
'seat0', '/org/freedesktop/login1/session/c2')]
我现在正在尝试使用以下方法获取循环中的每个数组元素:
for (uint32_t i = 0; i < ::g_variant_n_children(v); ++i)
{
GVariant *child = ::g_variant_get_child_value(v, i);
}
打印孩子时我得到:
<('2', uint32 1000, 'nidhoegger', 'seat0', objectpath '/org/freedesktop/login1/session/_32')>
到目前为止,一切都很好。现在我正在尝试使用单个项目g_variant_get
这边走:
gchar *id = NULL;
uint32_t uid = 0;
gchar *user = NULL;
gchar *seat = NULL;
gchar *session_path = NULL;
::g_variant_get(v, "(susso)", &id, &uid, &user, &seat, &session_path);
但它只给了我这个断言:
(process:12712): GLib-CRITICAL **: the GVariant format string '(susso)' has a type of '(susso)' but the given value has a type of 'v'
(process:12712): GLib-CRITICAL **: g_variant_get_va: assertion 'valid_format_string (format_string, !endptr, value)' failed
如果这是相关的:我生成了与之通信的代码gdbus-codegen
获取该值的函数具有以下签名:
gboolean login1_manager_call_list_sessions_sync (
Login1Manager *proxy,
GVariant **out_unnamed_arg0,
GCancellable *cancellable,
GError **error);
我究竟做错了什么?为什么它返回“v”作为值?