Non-blocking input in Gforth - time

Question

If we take a very simple counter using ncurses:
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <ncurses.h>
int main(void) {
struct timespec start;
clock_gettime(CLOCK_REALTIME, &start);
initscr();
cbreak();
nodelay(stdscr, TRUE);
{
int key = -1;
struct timespec delay, now;
do {
clock_gettime(CLOCK_REALTIME, &delay);
delay.tv_sec = 0;
delay.tv_nsec = 1000L * 1000L * 1000L - delay.tv_nsec;
nanosleep(&delay, NULL);
clock_gettime(CLOCK_REALTIME, &now);
mvprintw(1, 1, "%ld\n", (long)(now.tv_sec - start.tv_sec));
refresh();
key = getch();
if (key >= 0)
break;
} while (now.tv_sec - start.tv_sec < 60);
}
endwin();
return 0;
}
it aborts after pressing any key (OK, because of cbreak() using ctrl-C would always work without any extra effort...).
But we can make this more complicated, like adding a function to pause the counter or resetting it on the fly (+/- 1 second).
We definitely need a non-blocking keyboard input for this.
I wonder if it possible to do this in Gforth? OK, I know how to catch interrupts like SIGINT there, but something like above, working for any key or a any predetermined key?

Answer 1

Use key?, it returns a flag which is true if new input is available.
You can augment the following code as you see fit, but I think it explains the basic idea of running in a loop until a key is pressed.
: run-until-key ( -- )
0
begin
\ place your terminal code here
." Num:" dup . cr
1+
key? until drop ;
If you want to wait for a specific key, just add an if before the until:
...
key? if key 13 = else false then until
...
You can also add your timer there.