在已经运行循环上添加另一个计时器

Question

给定以下程序 -

#include <iostream>
#include <uv.h>

int main()
{
    uv_loop_t loop;
    uv_loop_init(&loop);

    std::cout << "Libuv version: " << UV_VERSION_MAJOR << "."
              << UV_VERSION_MINOR << std::endl;

    int r = 0;

    uv_timer_t t1_handle;
    r = uv_timer_init(&loop, &t1_handle);
    uv_timer_start(&t1_handle,
      [](uv_timer_t *t) { std::cout << "Timer1 called\n"; }, 0, 2000);

    uv_run(&loop, UV_RUN_DEFAULT);

    // second timer
    uv_timer_t t2_handle;
    r = uv_timer_init(&loop, &t2_handle);
    uv_timer_start(&t2_handle,
      [](uv_timer_t *t) { std::cout << "Timer2 called\n"; }, 0, 1000);

    uv_loop_close(&loop);
}

第二个计时器句柄永远不会在循环中运行，因为循环已经运行ning，并且永远不会打印 "Timer2 called"。所以我尝试在运行之后暂时停止循环，然后添加第二个计时器 -

....
uv_run(&loop, UV_RUN_DEFAULT);

// some work

uv_stop(&loop);
// now add second timer
uv_run(&loop, UV_RUN_DEFAULT); // run again
....

但这又一次不起作用，可能是因为在第一个循环开始后后面的行不会执行运行一个重复计时器。那么我应该如何为已经运行ning 的 uvloop 添加一个新的定时器句柄？

Answer 1

您说得对，在注册新句柄之前需要停止循环。在uv_run之后调用uv_stop函数是无法实现的，因为uv_run需要先return。例如，它可以通过使用句柄回调来停止它来实现。这是一个非常愚蠢的例子，说明如何使用现有的 Timer1 句柄完成它。它在第一个运行.

时恰好停止循环一次

#include <iostream>
#include <uv.h>

int main() {
  uv_loop_t loop;
  uv_loop_init(&loop);

  std::cout << "Libuv version: " << UV_VERSION_MAJOR << "." << UV_VERSION_MINOR
            << std::endl;

  int r = 0;

  uv_timer_t t1_handle;
  r = uv_timer_init(&loop, &t1_handle);
  *(bool *)t1_handle.data = true; // need to stop the loop
  uv_timer_start(&t1_handle,
                 [](uv_timer_t *t) {
                   std::cout << "Timer1 called\n";
                   bool to_stop = *(bool *)t->data;
                   if (to_stop) {
                     std::cout << "Stopping loop and resetting the flag\n";
                     uv_stop(t->loop);
                     *(bool *)t->data = false; // do not stop the loop again
                   }
                 },
                 0, 2000);
  uv_run(&loop, UV_RUN_DEFAULT);
  std::cout << "After uv_run\n";

  // second timer
  uv_timer_t t2_handle;
  r = uv_timer_init(&loop, &t2_handle);
  uv_timer_start(&t2_handle,
                 [](uv_timer_t *t) { std::cout << "Timer2 called\n"; }, 0,
                 1000);
  std::cout << "Start loop again\n";
  uv_run(&loop, UV_RUN_DEFAULT);

  uv_loop_close(&loop);
}

所以输出是

Libuv version: 1.9
Timer1 called
Stopping loop and resetting the flag
After uv_run
Start loop again
Timer2 called
Timer2 called
Timer1 called
Timer2 called
Timer2 called
Timer1 called

在已经运行循环上添加另一个计时器

add another timer on already running loop

c++

linux

c++11

libuv

在已经 运行 循环上添加另一个计时器

add another timer on already running loop

c++

linux

c++11

libuv

在已经运行循环上添加另一个计时器