#include <csignal>  // signal
#include <iostream> // cout endl
#include <unistd.h> // alarm pause

void alarma(int)
{
    std::cout << "alarma" << std::endl;
}

int main()
{
    signal(SIGALRM, alarma);
    alarm(1); // 1s

    std::cout << "hola" << std::endl;
    pause();
    std::cout << "adios" << std::endl;
}