Re: Building Readline 8.2 on MS-Windows using MinGW

[Chet Ramey]

On 7/12/24 7:40 AM, Eli Zaretskii wrote:

> I have a followup question.  Currently, reading input with timeout
> basically doesn't work on MS-Windows, and the ability to find out how
> many characters are available for input is severely limited (the
> calling application can only know if one or more input characters are
> available, but not how many, and the timeout specification to wait for
> input to become available is ignored).
>
> My question is how important is it to support this on MS-Windows?  The
> Posix implementation uses pselect and ioctl/fcntl and similar APIs,
> which won't work on MS-Windows, but there are ways of implementing the
> same functionality on Windows using alternative Windows-specific APIs.
> If these features are important to have, and their importance
> justifies making the sources use more #ifdef's and be slightly harder
> to read, I can work on adding them.
>
> Do you know if there are any applications which use Readline and can
> be built on Windows that need this functionality?

Hi, Eli. As you note, readline has had timeout support for forever, and
Windows has never supported it. That means things like bash `read -e -t'
don't work very well, or have to be implemented outside readline using
something like SIGALRM.

The current readline timeout implementation is new in readline-8.2, so I
don't know whether or not there are applications using it.

It was inspired by similar changes to bash, which used to use SIGALRM for
its read timeouts, and intended to provide a way for applications to use
readline timeouts without having to hijack SIGALRM. If you want to read
the discussion around it, start with

https://lists.gnu.org/archive/html/bug-bash/2021-02/msg00059.html

Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/

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