getch.c

/* Daniel LaBell */
/* /home/dlabell/src/C/getch.c */
/*  file-created: Tue Feb  3 02:00:37 1998 */
#include <termios.h>
#include <unistd.h>
#include <stdio.h>


int getch(void)
{
  struct termios term_settings,term_settings_saved;
  int x;
  if ( tcgetattr(STDIN_FILENO,&term_settings))
    return -1;
  term_settings_saved=term_settings;
  term_settings.c_lflag &= ~ICANON ;
  term_settings.c_lflag &= ~ECHO ;
  term_settings.c_cc[VMIN]=1 ;
  term_settings.c_cc[VTIME]=0;
  if (tcsetattr (STDIN_FILENO, TCSANOW, &term_settings) < 0 )
    return -1;
  x=getchar();
  tcsetattr (STDIN_FILENO, TCSANOW, &term_settings_saved);
  return x;
}

int getche(void)
{
  struct termios term_settings,term_settings_saved;
  int x;
  if ( tcgetattr(STDIN_FILENO,&term_settings))
    return -1;
  term_settings_saved=term_settings;
  term_settings.c_lflag &= ~ICANON ;
  term_settings.c_lflag |= ECHO ;
  term_settings.c_cc[VMIN]=1 ;
  term_settings.c_cc[VTIME]=0;
  if (tcsetattr (STDIN_FILENO, TCSANOW, &term_settings) < 0 )
    return -1;
  x=getchar();
  tcsetattr (STDIN_FILENO, TCSANOW, &term_settings_saved);
  return x;
}

/* getch pending or getch predicate if you like */
/* returns -1 if no char is pending, -2 if error, or value of  */

int getchp(void)
{
  struct termios term_settings,term_settings_saved;
  char c;
  int x;
  if ( tcgetattr(STDIN_FILENO,&term_settings))
    return -2;
  term_settings_saved=term_settings;
  term_settings.c_lflag &= ~ICANON ;
  term_settings.c_lflag &= ~ECHO ;
  term_settings.c_cc[VMIN]=0;
  term_settings.c_cc[VTIME]=0;
  if (tcsetattr (STDIN_FILENO, TCSANOW, &term_settings) < 0 )
    return -2;
  switch(read(STDIN_FILENO,&c,1))
    {
    case 0: x=-1; break;
    case -1: x=-2; break;
    default:     x=c;
    }
  tcsetattr (STDIN_FILENO, TCSANOW, &term_settings_saved);
  return x;
}



int getchpe(void)
{
  struct termios term_settings,term_settings_saved;
  char c;
  int x;
  if ( tcgetattr(STDIN_FILENO,&term_settings))
    return -2;
  term_settings_saved=term_settings;
  term_settings.c_lflag &= ~ICANON ;
  term_settings.c_lflag |= ECHO ;
  term_settings.c_cc[VMIN]=0;
  term_settings.c_cc[VTIME]=0;
  if (tcsetattr (STDIN_FILENO, TCSANOW, &term_settings) < 0 )
    return -2;
  switch(read(STDIN_FILENO,&c,1))
    {
    case 0: x=-1; break;
    case -1: x=-2; break;
    default:     x=c;
    }
  tcsetattr (STDIN_FILENO, TCSANOW, &term_settings_saved);
  return x;
}


/* test prog */
#include <stdlib.h>

int pause_message(const char * message)
{
  if ( message )
    puts(message);
  return getch();
}

int main(int arc, char * argv[])
{
  int x;
  char c;
  if (!(isatty(STDIN_FILENO)))
    {
      fprintf(stderr, "Not a terminal.\n");
      exit(2);
    }
  system ("ls");
  pause_message( "\npress almost any key to continue");
  puts("enter an integer number ");
  scanf( "%i", &x);
  printf( "5 + your number = %i\n", (5+x));
  pause_message( "\npress almost any key to continue");
  puts("Enter a single char: ");
  c=getch();
  printf("\n you typed %c, which is %hi in ascii\n", c, (short)c);
  pause_message( "\npress almost any key to continue");
  while ( getchp() < 0 )
    printf("After thats comes %hi\n", (short)++c);
  return  pause_message( "\npress almost any key to quit");
}