Re: [Bug-readline] Forwarding input from ncurses to readline

[Ulf Magnusson]

On Fri, Feb 20, 2015 at 3:30 PM, Chet Ramey <address@hidden> wrote:
> On 2/20/15 9:20 AM, Ulf Magnusson wrote:
>> On Fri, Feb 20, 2015 at 3:27 AM, Chet Ramey <address@hidden> wrote:
>>> On 2/18/15 9:43 PM, Ulf Magnusson wrote:
>>>
>>>> Re. rl_change_environment, there's this in the source:
>>>>
>>>> /* If this is non-zero, readline will set LINES and COLUMNS in the
>>>>    environment when it handles SIGWINCH. */
>>>> int rl_change_environment = 1;
>>>>
>>>> However, afaics readline does not update LINES and COLUMNS in the
>>>> SIGWINCH handler, at least not in the non-bash case. Is there some
>>>> motivation for this (besides being a bit tricky due to putenv/setenv not 
>>>> being
>>>> async-signal-safe)? The comment seems a little misleading either way. :)
>>>
>>> It does.  The SIGWINCH handler just sets a flag (_rl_caught_signal) and, as
>>> a side effect, calls any application-specific SIGWINCH handler to allow it
>>> to do the same.  When readline does its signal handling via the
>>> RL_CHECK_SIGNALS macro, it notices that it caught SIGWINCH and calls
>>> _rl_signal_handler with SIGWINCH as the argument.  _rl_signal_handler
>>> calls rl_resize_terminal, which calls _rl_get_screen_size, which eventually
>>> calls sh_set_lines_and_columns.
>>>
>>
>> Hmm... it's odd that ncurses doesn't pick up the updated LINES and COLUMNS
>> variables then. It also forwards the signal in its SIGWINCH handler.
>
> I thought you said you had forced readline to not catch signals; if
> readline doesn't install signal handlers none of this is relevant.
>

That was later. I'm thinking of what caused the original problem.
Should have been
clearer.

/Ulf