keytest.c

#include <stdio.h>
#include <unistd.h>
#include <termios.h>
#include <sys/ioctl.h>
#include <stdlib.h>
#include <sys/poll.h>
#include <stropts.h>


int getkey()
{
  char k;

  read(STDIN_FILENO, &k, 1);

  return k;
}


int hasInput()
{
  struct pollfd fds;
  int pres;

  fds.fd=STDIN_FILENO;
  fds.events=POLLIN;
  pres = poll(&fds, 1, 0);

  return pres==1;
}



void setMode(int _echo, int _canonical, int _signal, int _special)
{
  struct termios t;

  //get the current termios
  if(tcgetattr(STDIN_FILENO, &t) == -1) {
    return;  //TODO Exception Handling
  }


  //echo handling
  if(_echo) {
    //set the ECHO flag
    t.c_lflag |= ECHO;
  } else {
    //clear the ECHO flag
    t.c_lflag &= ~ECHO;
  }

  //canonical handling
  if(_canonical) {
    t.c_lflag |= ICANON;
    t.c_iflag |= ICRNL;
  } else {
    t.c_lflag &= ~ICANON;
    t.c_iflag &= ~ICRNL;
  }

  //singal handling
  if(_signal) {
    t.c_lflag |= ISIG | IEXTEN;
  } else {
    t.c_lflag &= ~(ISIG | IEXTEN);
  }


  //special processing handling
  if(_special) {
    t.c_iflag |= BRKINT | INPCK | IGNBRK | ISTRIP | IGNCR | IXON | INLCR | PARMRK;
    t.c_oflag |= OPOST;
  } else {
    t.c_iflag &= ~(BRKINT | INPCK | IGNBRK | ISTRIP | IGNCR | IXON | INLCR | PARMRK);
    t.c_oflag &= ~OPOST;
  }

  t.c_cc[VMIN] = 1;  
  t.c_cc[VTIME] = 0;
  
  //set the ttye info
  if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &t) == -1)
    return;  //TODO exception handling
}


int main()
{
  int x;

  setMode(0, 0, 1, 1);
  
  do {
    x = getkey();
    printf("%d\n", x);
    usleep(30000);
  } while(hasInput());
  return 0;
}