get_char.cpp

#include <stdio.h>
#include <stdlib.h>
#include <termios.h>
#include <unistd.h>
#include <errno.h>

struct getch_flag
{
  char line:1;
  char echo:1;
  getch_flag() : line(0), echo(0) {}
} flag;

int get_char();

int main(int argc, char* argv[])
{
  int result;
  while((result=getopt(argc,argv,"le"))!=-1){
    switch(result){
    case 'l':
      flag.line = 1;
      break;
    case 'e':
      flag.echo = 1;
      break;      
    case '?':
      return EXIT_FAILURE;
      break;
    }
  }
  return get_char();
}

int get_char()
{
  struct termios save_term;
  struct termios temp_term;
  char ch;
  
  /* get term attributes */
  errno = 0;
  if(tcgetattr(fileno(stdin), &save_term) == -1){
    perror("tcgetattr failure");
    return EXIT_FAILURE;
  }else{
    temp_term = save_term;
  }
  
  /* non canonical */
  temp_term.c_lflag &= ~ICANON;
  /* finish read char */
  temp_term.c_cc[VMIN] = 1;
  /* no echo */
  if(!flag.echo)
  temp_term.c_lflag &= ~ECHO;
  
  errno = 0;
  if(tcsetattr(fileno(stdin), TCSANOW, &temp_term) == -1){
    perror("tcsetattr(temp_term) failure");
    return EXIT_FAILURE;
  }
  
  if(flag.line) {
    while(1) {
      ch = fgetc(stdin);
      if(ch == '\r' || ch == '\n'){
	break;
      } else {
	fputc(ch, stdout);
      }
    }
  } else {
    ch = fgetc(stdin);
    fputc(ch, stdout);
  }
  /* reset */
  errno = 0;
  if(tcsetattr(fileno(stdin), TCSANOW, &save_term) == -1){
    perror("tcsetattr(save_term) failure");
    return EXIT_FAILURE;
  }
  return EXIT_SUCCESS;
}