Key polling on Linux in plain C

key_poll.c

#define KEY_POLL_TEST
struct termios poll_before, poll_new;
struct timeval poll_tv;
fd_set poll_fs;

int poll_init(){
    poll_tv.tv_usec = POLL_TIMEOUT_MICROSECONDS;
    poll_tv.tv_sec = POLL_TIMEOUT_SECONDS;

    if(tcgetattr(STDIN_FILENO, &poll_before) != 0) return 1;
    poll_new = poll_before;
    poll_new.c_lflag &= ~(ICANON | ECHO);
    if(tcsetattr(STDIN_FILENO, TCSANOW, &poll_new) != 0) return 1;
    return 0;
}

int poll_close(){
    return (tcsetattr(STDIN_FILENO, TCSANOW, &poll_before) == 0) ? 0 : 1;
}

void poll_set_timeout(unsigned int seconds, unsigned int micro_sec){
    poll_tv.tv_usec = micro_sec;
    poll_tv.tv_sec = seconds;
}

int poll_key(){
    FD_ZERO(&poll_fs);
    FD_SET(STDIN_FILENO, &poll_fs);
    select(STDIN_FILENO + 1, &poll_fs, 0, 0, &poll_tv);
    if (FD_ISSET(STDIN_FILENO, &poll_fs)) return getchar();
    else return 0;
}

#ifdef KEY_POLL_TEST
int main(){
    poll_init();

    while(1){
        int c = poll_key();
        if(c != 0){
            printf("key %d\n", c);
            if(c == 10) break;
        }
    }
    return poll_close();
}
#endif