How to interrupt wait on input in C++?

Question

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Good day!
There is an infinite loop that accepts user commands. In the loop, respectively, there is a line: In a certain situation, I need to exit the loop by terminating the program, is it possible to interrupt the input waiting (without resorting to using std::exit)?
std::cin.getline(buffer, strlen(buffer));

Answer 1

just call break

In a certain situation

will not work?
UPDATE: if you do not want to block on input, then as far as I remember, C ++ can only help you here with the readsome method. Other options I know are system dependent, like posix aio.

Answer 2

Not the best practice, but you can just close the stream that is asking stdin. Example with POSIX threads:

#include <stdio.h>
#include <unistd.h>
#include <pthread.h>

void *worker(void *data)
{
    char buf[128];
    while(fgets(buf, sizeof(buf), stdin))
    {
  puts(buf);
    }
}

int main(int argc, char **argv)
{
    pthread_t t;
    pthread_create(&t, NULL, worker, NULL);
    sleep(3);
    pthread_cancel(t);
    pthread_join(t, NULL);
    return 0;
}

Sketched in C, but the essence should be clear.

Answer 3

This function will not help you in principle, you need to use in this case you need functions that return the result immediately without waiting for actions from the outside, for example peek and organize your own input loop. Well, or read.