How to select on STDIN_FILENO ignoring signals?

Please check the following code

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <termios.h>
#include <unistd.h>
#include <sys/types.h>
#include <signal.h>
#include <sys/time.h>
#include <time.h>

#define CLOCKID CLOCK_REALTIME
#define SIG SIGRTMIN
int reset = 0;
void changemode(int);
int  kbhit(void);
int pfds[2];

static void handler(int sig, siginfo_t *si, void *uc)
{
    write(pfds[1], "reset", 6);
}

int main(void)
{
    int ch;
    timer_t timerid;
    struct sigaction sa;
    struct itimerspec its;
    struct sigevent sev;
    long long freq_nanosecs;
    char buf[30];

    pipe(pfds);

    sa.sa_flags = 0;
    sa.sa_sigaction = handler;
    sigemptyset(&sa.sa_mask);
    if (sigaction(SIG, &sa, NULL) == -1)
    {
        printf("Error\n");
        exit(1);
    }

    changemode(1);

    sev.sigev_notify = SIGEV_SIGNAL;
    sev.sigev_signo = SIG;
    sev.sigev_value.sival_ptr = &timerid;
    if (timer_create(CLOCKID, &sev, &timerid) == -1)
    {
        printf("Error timer_create");
        exit(1);
    }

    its.it_value.tv_sec = 1;
    its.it_value.tv_nsec = 0;
    its.it_interval.tv_sec = its.it_value.tv_sec;
    its.it_interval.tv_nsec = its.it_value.tv_nsec;

    if (timer_settime(timerid, 0, &its, NULL) == -1)
    {
        printf("Error timer_settime");
        exit(1);
    }

    while(1)
    {
        if (kbhit())
        {
            ch = getchar();
            printf("%d %c\n", ch, ch);
            if (ch == 'q')
            {
                printf("\nQuitting...\n");
                break;
            }
        }
        else
        {
            memset(buf, 0, 30);
            read(pfds[0], buf, 6);
            printf("\n%s", buf);
        }
    }

    changemode(0);
    return 0;
}

void changemode(int dir)
{
    static struct termios oldt, newt;

    if ( dir == 1 )
    {
        tcgetattr( STDIN_FILENO, &oldt);
        newt = oldt;
        newt.c_lflag &= ~( ICANON | ECHO );

        tcsetattr( STDIN_FILENO, TCSANOW, &newt);
    }
    else
        tcsetattr( STDIN_FILENO, TCSANOW, &oldt);
}

int kbhit (void)
{
    fd_set rdfs;

    FD_ZERO(&rdfs);
    FD_SET (STDIN_FILENO, &rdfs);
    FD_SET (pfds[0], &rdfs);

    select(FD_SETSIZE, &rdfs, NULL, NULL, NULL);
    return FD_ISSET(STDIN_FILENO, &rdfs);

}

But whenever the signal SIGRTMIN is generated STDIN_FILENO is set (FD_ISSET) althought i've not entered anything in the terminal. How to make select ignore STDIN_FILENO when SIGRTMIN is generated by the timer?

If you are using Linux, you should use pselect instead of select.

If not, you should check the error code returned by select. If it is EINTR, it is possible (but I am not sure) that you might have to call select again to check the status of the fds.