Lectura de tecla Linux no bloquea

#include <iostream>
#include <unistd.h>
#include <termios.h>
#include <sys/time.h>

 using namespace std;
int unix_text_kbhit(void)
{
    struct timeval tv = { 0, 0 };
    fd_set readfds;

    FD_ZERO(&readfds);
    FD_SET(STDIN_FILENO, &readfds);

    return select(STDIN_FILENO + 1, &readfds, NULL, NULL, &tv) == 1;
}

void mode_raw(int activer) //Terminal en modo RAW
{
    static struct termios cooked;
    static int raw_actif = 0;

    if (raw_actif == activer)
        return;

    if (activer)
    {
        struct termios raw;

        tcgetattr(STDIN_FILENO, &cooked);

        raw = cooked;
        cfmakeraw(&raw);
        tcsetattr(STDIN_FILENO, TCSANOW, &raw);
    }
    else
        tcsetattr(STDIN_FILENO, TCSANOW, &cooked);

    raw_actif = activer;
}
int main (){
    while (true){
        mode_raw(1);
        if (unix_text_kbhit()!=0){mode_raw(0);cout<<(char) getchar()<<endl;}
    }
    return 0;
}