Re: stty: problem if IXON enabled and DC3 char was received

[Pádraig Brady]

On 04/01/16 20:41, Tomas Krcka wrote:
> On 01/04/2016 04:10 PM, Jim Meyering wrote:
>> On Mon, Jan 4, 2016 at 7:07 AM, Bernhard Voelker
>> <address@hidden> wrote:
>>> On 01/04/2016 01:34 PM, Pádraig Brady wrote:
>>>> --- a/NEWS
>>>> +++ b/NEWS
>>>> @@ -47,6 +47,9 @@ GNU coreutils NEWS
>>>> -*- outline -*-
>>>>     is reusable by most shells, with non-printable characters escaped
>>>>     with the POSIX proposed $'...' syntax.
>>>>
>>>> +  stty now supports the -i, --immediate option, to apply settings
>>>> +  without waiting for transmission of any pending output.
>>>> +
>>>
>>> s/-i/-I/
>>>
>>>> --- a/src/stty.c
>>>> +++ b/src/stty.c
>>> ...
>>>> @@ -522,7 +523,7 @@ usage (int status)
>>>>     else
>>>>       {
>>>>         printf (_("\
>>>> -Usage: %s [-F DEVICE | --file=DEVICE] [SETTING]...\n\
>>>> +Usage: %s [-F DEVICE | --file=DEVICE] [-I] [SETTING]...\n\
>>>>     or:  %s [-F DEVICE | --file=DEVICE] [-a|--all]\n\
>>>>     or:  %s [-F DEVICE | --file=DEVICE] [-g|--save]\n\
>>>>   "),
>>>> @@ -538,6 +539,9 @@ Print or change terminal characteristics.\n\
>>>>     -g, --save         print all current settings in a stty-readable
>>>> form\n\
>>>>     -F, --file=DEVICE  open and use the specified DEVICE instead of
>>>> stdin\n\
>>>>   "), stdout);
>>>> +      fputs (_("\
>>>> +  -i, --immediate    apply setting without waiting for pending
>>>> transmission\n\
>>>> +"), stdout);
>>>
>>> Likewise.
>>>
>>> Otherwise +1.
>> Patch looks fine.
>> You might want to add a URL linking to this discussion in the commit log;
>> it provides a fine "why would I want this" use case.
> Patch is OK, just change -i to capital -I in help as Berny mentioned.
> And I would also append the use case (scenario) when it's good to use it.
> I spent a lots of time to find out where was the problem, so it can help 
> someone.

Upon consideration I dislike the asymmetry with providing
an --immediate option but without a converse option
that could be used on non GNU systems, or on distros
that decide to change the default "draining" operation.

In the attached I've used a negatable "drain" special setting,
which I think is better due to being directly associated with
settings, and being reversible using standard stty syntax.

thanks,
Pádraig

stty-drain.patch
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