libuv: uv_timer_stop() does not stop and reset the timer - c++

Question

The uv_timer_stop() does not appear to stop and reset the timer. How can I stop and reset the timer correctly?
#include <iostream>
#include <thread>
#include <unistd.h> // usleep
#include <uv.h>
uv_loop_t *loop;
uv_timer_t timer_req;
float timerSeconds = 2.0f;
float sleepSeconds = 1.0f;
void run() {
while (true) uv_run(loop, UV_RUN_DEFAULT);
}
void timerCallback(uv_timer_t* handle) {
std::cout << "Callback" << std::endl;
}
int main() {
loop = uv_default_loop();
std::thread t(run);
uv_timer_init(loop, &timer_req);
while (true) {
std::cout << "sleep" << std::endl;
uv_timer_start(&timer_req, timerCallback, 1000*timerSeconds, 0);
usleep(1000*1000*sleepSeconds);
uv_timer_stop(&timer_req);
};
return 0;
}
output on Debian Linux with libuv1-dev 1.24.1:
$ g++ main.cc -o main `pkg-config --libs libuv`
$ ./main
sleep
sleep
sleep
sleep
sleep
Callback
sleep
^C
Expected output: The timer is set to call the callback after two seconds (float timerSeconds = 2.0f). But we stop (and restart) the timer after every second (float sleepSeconds=1.0f), so the timer should never run long enough for the callback to be executed and the output should show only the 'sleep' messages, instead of the 'Callback' message. That is, it should be:
$ g++ main.cc -o main `pkg-config --libs libuv`
$ ./main
sleep
[...]
I've tried:
stopping the timer inside the callback
reinitialising the timer every time: using uv_timer_init() inside the while loop, before calling uv_timer_start()
Why I am doing this: I'm writing a program to detect the long-press of a button (a short-press of a button triggers a different action). There is a callback to detect a button-press, and a button-depress. The button-press should start the timer, and button-depress should stop the timer. If the button has been pressed down long enough (two seconds), the timer callback executes, and if we reach this callback, then we know that the button has been long-pressed.