显示 X11 的空闲时间
// gcc main.c -lX11 -lXss
#include <stdio.h>
#include <X11/extensions/scrnsaver.h>
int main(void) 
{
    Display* dpy = XOpenDisplay(NULL);
    if (!dpy) 
        return 1;
    XScreenSaverInfo* info = XScreenSaverAllocInfo();
    while(1)
    {
        XScreenSaverQueryInfo(dpy, DefaultRootWindow(dpy), info);
        printf("%u\n", info->idle);
    }
    return 0;
}