1 /* Noncanonical Mode Example
2 Copyright (C) 1991-2021 Free Software Foundation, Inc.
3
4 This program is free software; you can redistribute it and/or
5 modify it under the terms of the GNU General Public License
6 as published by the Free Software Foundation; either version 2
7 of the License, or (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, see <https://www.gnu.org/licenses/>.
16 */
17
18 #include <unistd.h>
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <termios.h>
22
23 /* Use this variable to remember original terminal attributes. */
24
25 struct termios saved_attributes;
26
27 void
reset_input_mode(void)28 reset_input_mode (void)
29 {
30 tcsetattr (STDIN_FILENO, TCSANOW, &saved_attributes);
31 }
32
33 void
set_input_mode(void)34 set_input_mode (void)
35 {
36 struct termios tattr;
37 char *name;
38
39 /* Make sure stdin is a terminal. */
40 if (!isatty (STDIN_FILENO))
41 {
42 fprintf (stderr, "Not a terminal.\n");
43 exit (EXIT_FAILURE);
44 }
45
46 /* Save the terminal attributes so we can restore them later. */
47 tcgetattr (STDIN_FILENO, &saved_attributes);
48 atexit (reset_input_mode);
49
50 /*@group*/
51 /* Set the funny terminal modes. */
52 tcgetattr (STDIN_FILENO, &tattr);
53 tattr.c_lflag &= ~(ICANON|ECHO); /* Clear ICANON and ECHO. */
54 tattr.c_cc[VMIN] = 1;
55 tattr.c_cc[VTIME] = 0;
56 tcsetattr (STDIN_FILENO, TCSAFLUSH, &tattr);
57 }
58 /*@end group*/
59
60 int
main(void)61 main (void)
62 {
63 char c;
64
65 set_input_mode ();
66
67 while (1)
68 {
69 read (STDIN_FILENO, &c, 1);
70 if (c == '\004') /* @kbd{C-d} */
71 break;
72 else
73 putchar (c);
74 }
75
76 return EXIT_SUCCESS;
77 }
78