使用xlib检测正在运行的屏幕保护程序

这是我到目前为止的代码：

/* LDFLAGS='-L/usr/X11R6/lib/ -lX11 -lXext -lXss' make xidle */
#include <stdio.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/extensions/scrnsaver.h>

int
main(int argc,char *argv[])
{
    XScreenSaverInfo info;
    Display *dpy = XOpenDisplay(NULL);

    if(NULL == dpy) {
        fprintf(stderr,"failed to open displayn");
        return 1;
    }

    int a = 0;
    int b = 0;
    XScreenSaverQueryExtension(dpy,&a,&b);
    printf("%d %dn",a,b);

    XScreenSaverQueryInfo(dpy,RootWindow(dpy,DefaultScreen(dpy)),&info);
    printf("%d %d %d %dn",info.state,info.til_or_since,info.idle,info.kind);
    return 0;
}

但是info.state总是3(ScreenSaverDisabled).我用xscreensaver和gnome-screensaver对此进行了测试.

这是一些示例输出：

92 0
3 0 9903 0

它与运行的屏幕保护程序相同或没有(当然除了info.idle).

附加信息：

$X -version
X.Org X Server 1.13.0
Release Date: 2012-09-05
X Protocol Version 11,Revision 0

窗口管理器：i3

发行版：Arch Linux

编辑：
在[this] [1]的帮助下,我创建了一个xcb版本,但也无效.要在我的测试过程中排除错误,这里是：
我有这个代码在无限循环中运行,而我在后台运行xscreensaver.为了实际激活屏幕保护程序,我使用xscreensaver-command –activate

#include <stdlib.h>
#include <stdio.h>
#include <xcb/xcb.h>
#include <xcb/screensaver.h>

static xcb_connection_t * connection;
static xcb_screen_t * screen;

/**
 * Connects to the X server (via xcb) and gets the screen
 */
void magic_begin () {
    connection = xcb_connect (NULL,NULL);
    screen = xcb_setup_roots_iterator (xcb_get_setup (connection)).data;
}

/**
 * Asks X for the time the user has been idle
 * @returns idle time in milliseconds
 */
unsigned long magic_get_state () {
    xcb_screensaver_query_info_cookie_t cookie;
    xcb_screensaver_query_info_reply_t *info;

    cookie = xcb_screensaver_query_info (connection,screen->root);
    info = xcb_screensaver_query_info_reply (connection,cookie,NULL);

    int state = info->state;

    return state;
}

int main(int arc,char *argv[])
{
    magic_begin();
    int state = magic_get_state();
    printf("state: %dn",state);
}


[1]: https://stackoverflow.com/questions/9049087/with-x11-how-can-i-get-the-users-time-away-from-keyboard-while-ignoring-cert