Hi all,

I have a small function for checking whether the keyboard has been pressed without blocking. I tried to compile the program using g++ and another time with gcc. But nothing works correctly.

This is function
int checkKeyboard() {
  fd_set readvec;
  struct timeval timeout;
  int ret, stdin_fd;

  timeout.tv_sec = 0;
  timeout.tv_usec = 0;
  stdin_fd = 0;
  FD_SET(stdin_fd, &readvec);

  ret = select(1, &readvec, NULL, NULL, &timeout);
  if (ret == -1) {  // got an error
    if (errno != EINTR)  
      printf("select() error while attempting to read text input.\n");
    return FALSE;
  } else if (ret == 0) {
    return FALSE;  // select timed out
  return TRUE;
This is the whole testing program :
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#define TRUE 1
#define FALSE 0

//The previous code segment
int checkKeyboard() {
int main(int argc, char* argv[]) {
  int i;
  for (i=0; i<100000; i++) {
     if (vmd_check_stdin()>0) {
       printf("Keyboard was pressed. Terminating...\n");
       return 0;
     } else {
       printf("i = %d\n", i);
  return 0;
The program loops and exits when the user presses any key in the keyboard. When I run it, program loops and never exits although I pressed the keyboard multiple times while its counting!!After the program finish, the characters are printed to the console as if they all have been buffered while the program ran

Does anyone have an idea about this strange problem??