sleep 1s after UI_DEV_CREATE

[tillthendofworld]

int fd = open("/dev/uinput", O_WRONLY | O_NONBLOCK);
......
ioctl(fd, UI_DEV_CREATE);
/*
* On UI_DEV_CREATE the kernel will create the device node for this
* device. We are inserting a pause here so that userspace has time
* to detect, initialize the new device, and can start listening to
* the event, otherwise it will not notice the event we are about
* to send.
*/
//sleep(1);
write(...); // not work, if not sleep(1)

https://kernel.org/doc/html/v4.12/input/uinput.html#examples

    '''  a not work example, draw circle inf, 
         the first BTN_TOUCH,1 is ignored because the device not created'''
    def draw_cricle(x0=600,y0=1493,n=4,r=50):
         n=int(n)
         for k in range(0,n):
             angle = 2*math.pi*(k/n+3/4)
             x = r*math.cos(angle)+x0
             y = r*math.sin(angle)+y0
             yield int(x),int(y)
     code= ''
     self.TRACKING_ID+=1
     code+= f'// {x0},{y0}\n'
     code+= f'emit(uinputfd, EV_ABS, ABS_MT_SLOT, {int(slot_id)});\n'
     code+= f'emit(uinputfd, EV_ABS, ABS_MT_TRACKING_ID, {int(self.TRACKING_ID)});\n'
     code+= f'emit(uinputfd, EV_ABS, ABS_MT_POSITION_X, {int(x0)});\n'
     code+= f'emit(uinputfd, EV_ABS, ABS_MT_POSITION_Y, {int(y0)});\n'
     code+= f'emit(uinputfd, EV_KEY, BTN_TOUCH, 1);\n'
     code+= f'emit(uinputfd, EV_SYN, SYN_REPORT, 0);\n'
     code+= '''while(1) {\n'''
     for idx,(x,y) in enumerate(draw_cricle()):
         code+= f'  usleep({int(s*1000000)});//{s}s\n' #s=0.01 s
         code+= f'// move {x},{y}\n'
         # code+= f'emit(uinputfd, EV_ABS, ABS_MT_SLOT, {int(slot_id)});\n'
         code+= f'emit(uinputfd, EV_ABS, ABS_MT_POSITION_X, {int(x)});\n'
         code+= f'emit(uinputfd, EV_ABS, ABS_MT_POSITION_Y, {int(y)});\n'
         code+= f'emit(uinputfd, EV_SYN, SYN_REPORT, 0);\n'
     code+= '''}         \n'''