On Sun, 13 Jul 2025 20:34:56 +0900
Takashi Yano wrote:
> On Sun, 13 Jul 2025 11:40:10 +0200
> Christoph Reiter wrote:
> > I'm having the problem that under cygwin flushing stdin for some reason
> > doesn't
> > work when running in mintty. It works when running cygwin in the Windows
> > terminal though. In my case the program using this is pacman, where it asks
> > various questions and if you hit some keys in-between questions they leak
> > into
> > the next one, resulting in invalid input.
> >
> > Example program showing the problem. Type some text in the first 5 seconds,
> > and
> > see the input leak into the next input. Any ideas/workarounds welcome.
> >
> > ```c
> > // gcc -o flush_stdin flush_stdin.c
> > #include <stdio.h>
> > #include <unistd.h>
> > #include <termios.h>
> >
> > int main() {
> > printf("type something in the next 5 secs\n");
> > for (int i=0; i < 5; i++) {
> > sleep(1);
> > printf("%d\n", i);
> > }
> >
> > // Flush stdin
> > int fd = fileno(stdin);
> > if (fd != -1) {
> > printf("flushing stdin\n");
> > if (tcflush(fd, TCIFLUSH) == -1) { // this doesn't seem to do
> > anything
> > perror("Error flushing stdin");
> > return 1;
> > }
> > } else {
> > perror("Error getting file descriptor for stdin");
> > return 1;
> > }
> >
> > char buffer[100];
> > printf("Enter some text:\n");
> > fgets(buffer, sizeof(buffer), stdin);
> > printf("You entered: %s\n", buffer);
> >
> > return 0;
> > }
> > ```
>
> Thanks for the report.
>
> This seems to be a bug of pty code. If you enter 'return' key
> in the first 5 sec, the input will be flushed.
>
> I'll look into that.
Fixed.
https://cygwin.com/pipermail/cygwin-patches/2025q3/014128.html
--
Takashi Yano <takashi.y...@nifty.ne.jp>
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