Switch a fd between blocking and non-blocking mode?

[Jeffrey Walton]

On Wed, Nov 13, 2019 at 4:59 AM Konstantin Andreev <andreev at swemel.ru> wrote:
>
> I have looked into the sources of the kernel 4.19.13.
>
> After the series of checks the fcntl(F_SETFL) just stores flags into the file descriptor, and that's all:

Ack, thanks. I did not think the kernel discarded the data when
switching the mode. (a tcflush or tcdrain may do it, but I did not
call them).

I'm almost certain there's a bug in the firmware on the modem I am using.

Jeff