1 /*
2 C non-blocking keyboard input
3 http://stackoverflow.com/questions/448944/c-non-blocking-keyboard-input
4 */
5
6 #include <stdlib.h>
7 #include <string.h>
8 #include <sys/select.h>
9 #include <termios.h>
10 #include <unistd.h>
11 #include "getch.h"
12
13 struct termios orig_termios;
14
reset_terminal_mode()15 void reset_terminal_mode()
16 {
17 tcsetattr(0, TCSANOW, &orig_termios);
18 }
19
set_conio_terminal_mode()20 void set_conio_terminal_mode()
21 {
22 struct termios new_termios;
23
24 /* take two copies - one for now, one for later */
25 tcgetattr(0, &orig_termios);
26 memcpy(&new_termios, &orig_termios, sizeof(new_termios));
27
28 /* register cleanup handler, and set the new terminal mode */
29 atexit(reset_terminal_mode);
30 cfmakeraw(&new_termios);
31 new_termios.c_oflag |= OPOST;
32 tcsetattr(0, TCSANOW, &new_termios);
33 }
34
kbhit()35 int kbhit()
36 {
37 struct timeval tv = { 0L, 0L };
38 fd_set fds;
39 FD_ZERO(&fds); // not in original posting to stackoverflow
40 FD_SET(0, &fds);
41 return select(1, &fds, NULL, NULL, &tv);
42 }
43
getch()44 int getch()
45 {
46 int r;
47 unsigned char c;
48 if ((r = read(0, &c, sizeof(c))) < 0) {
49 return r;
50 } else {
51 return c;
52 }
53 }
54
55 #if 0
56 int main(int argc, char *argv[])
57 {
58 set_conio_terminal_mode();
59
60 while (!kbhit()) {
61 /* do some work */
62 }
63 (void)getch(); /* consume the character */
64 }
65 #endif
66