Why simple read string from non blocking IO in C behaves oddly in loop?

Question

I have just encountered a problem which I couldn't found the reason. The code works as Below:

1. There is a while loop which does a lot of stuff in the middle (Does not even written), and has a non-blocking IO to receive the end process command (which is a string).
2. At any time, a user could come and wants to finish the process. He/She would press some keys and then press the [Enter] button.
3. After select find out there is an input, it uses the input string and evaluates with the EXIT string and end the process.

Now the problem is when I use the exitFlag string as the termination key it just don't accept it and keeps writing <the printf() statement> until i hit cntrl+c. I have tried scanf(), fputs(), fread() to recieve input string from stdin and also used fflush(stdin) and fflush(stdout) to clear the std buffers.

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


int main() 
{ 
    fd_set          s;
    struct timeval  timeout;
    timeout.tv_sec = 3;
    timeout.tv_usec = 0;
    char exitFlag[10];
    int sFlag;
    printf("Enter \"EXIT\" to End the Process\n"); 
    while (1)
    {
        fflush(stdin); fflush(stdout);
        FD_ZERO(&s);
        FD_SET(STDIN_FILENO, &s);
        timeout.tv_sec = 3; timeout.tv_usec = 0;
        sFlag = select(STDIN_FILENO+1, &s, NULL, NULL, &timeout);
        printf("%d: ", sFlag);
        if      (sFlag < 0) _exit(0);
        else if (sFlag == 0) 
        {
            printf("-\n");
            fflush(stdin); fflush(stdout);
        }
        else     
        {
            fflush(stdin); fflush(stdout);
            scanf("%[^\n]s", &exitFlag); // fgets( exitFlag, 10, stdin); // fread( exitFlag, 10, 1 ,stdin);
            printf("You have Pressed %s, Enter \"EXIT\" to End the Process: ", exitFlag); 
            printf("%s\n", exitFlag);
            if ( memcmp(&exitFlag, "EXIT", 4) == 0 ) break;
        }
    }

  return 0; 
}

Ironically, I don't encounter similar problem when using char as the termination key input rather than string. I would be very thankful if someone explains where I made mistake in the IO or any other place.

I have also reviewed prior questions carefully but they had seemed to work with a single keyboard press which was not safe for common use!

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


int main() 
{ 
    fd_set          s;
    struct timeval  timeout;
    timeout.tv_sec = 3;
    timeout.tv_usec = 0;
    char exitFlag;
    int sFlag;
    while (1)
    {
        fflush(stdout);
        FD_ZERO(&s);
        FD_SET(STDIN_FILENO, &s);
        timeout.tv_sec = 3; timeout.tv_usec = 0;
        sFlag = select(STDIN_FILENO+1, &s, NULL, NULL, &timeout);
        if      (sFlag < 0) _exit(0);
        else if (sFlag == 0) 
        {
            fflush(stdout);
            printf("-\n");
        }
        else     
        {
            fflush(stdin);
            scanf("%c", &exitFlag);
            printf("You have Pressed %c, Press E to exit: ", exitFlag); 
            printf("%c\n", exitFlag);
            fflush(stdout);
            if ( exitFlag =='E' ) break;
        }
    }

  return 0; 

}