Glenn Kasten | 99478f4 | 2016-12-07 10:30:33 -0800 | [diff] [blame] | 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 | |
| 15 | void reset_terminal_mode() |
| 16 | { |
| 17 | tcsetattr(0, TCSANOW, &orig_termios); |
| 18 | } |
| 19 | |
| 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 | |
| 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 | |
| 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 |