Linux 内核事件:timeval 或 timespec [英] Linux kernel event: timeval or timespec

问题描述

我正在从 linux 内核读取(触摸)事件.我想记录这些事件的时间，但我不知道这些是作为 timespec 还是 timeval 传递的.有人能指出我正确的方向吗?

I am reading (touch)event from the linux kernel. I'd like to log the time of these events, but I am unaware whether these are passed as timespec or timeval. Could anyone point me in the right direction?

示例代码(从缓冲区读取事件后)

Example code (after the events are read from the buffer)

switch(evnt.code) {
    case ABS_X:
    case ABS_Y:
      break;
        case ABS_MT_SLOT: 
       // this one sets the digit (virtual representation of the finger)
           current.setSlot(evnt.value);
          break;
    case ABS_MT_POSITION_X:
      current.setX(evnt.value, evnt.time);
      break;
    case ABS_MT_POSITION_Y:
      current.setY(evnt.value, evnt.time);
      break;
    case ABS_MT_TRACKING_ID:
      current.setActive(evnt.value >= 0, evnt.time);
      break;
    default:
      W_MOD("EV_ABS, unhandled event code " << evnt.code);
    }

和进程函数之一:

inline void setY(int value, struct timeval KernelTime)
{
    if (slot < ndigits) {
    // store both time and value
        digit[slot].y = value;
        digit[slot].TimeOfEvent = KernelTime.tv_sec*1000000 +  KernelTime.tv_usec;;
        digit[slot].changed = true;
}
}

使用 timeval 它可以工作，但这也可能是自动的幸运类型转换吗?

With timeval it works, but could this also be an automatic lucky typecasting?

当我写完这篇文章时，我想出了一些方法来检查它.读取 linux 内核事件的代码evtest"是开源的.在 第 1060 行 上，他们使用 timeval 结构来报告活动时间.我猜这是肯定的答案:或者它仍然是一个无法预料的类型转换?

as soon as I wrote this I figured some way to check it. the code 'evtest' which reads linux kernel events is open source. On line 1060 they use a timeval struct to report the event time. I am guessing this is the definite answer: or could it still be a unforeseen typecasting?

推荐答案

有人能指出我正确的方向吗?

Could anyone point me in the right direction?

请参阅文档/input/input.rst.
从 /dev/input/eventX 设备读取返回 struct input_event 的数据，其第一个成员是 struct timeval time;

See Documentation/input/input.rst.
Reading from a /dev/input/eventX device returns data for a struct input_event, whose first member is struct timeval time;

Event interface
===============
...
    struct input_event {
        struct timeval time;
        unsigned short type;
        unsigned short code;
        unsigned int value;
    };

``time`` is the timestamp, it returns the time at which the event happened.

这篇关于Linux 内核事件:timeval 或 timespec的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！