Re: lib/58955: libedit: rl_event_hook not called when output is piped to another process

["Michael Rosen via gnats" <gnats-admin%NetBSD.org@localhost>]

The following reply was made to PR lib/58955; it has been noted by GNATS.

From: Michael Rosen <mrrosen%alumni.cmu.edu@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: lib-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost
Subject: Re: lib/58955: libedit: rl_event_hook not called when output is piped
 to another process
Date: Thu, 9 Jan 2025 15:19:31 -0800

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 >From my tests, readline works the same for interactive and non-interactive
 processes. Just changing the example code to use "#include
 <readline/readline.h>" and linking against GNU readline, rl_event_hook is
 called periodically in either case.
 
 It's worth noting that GNU readline does rate limit calling rl_event_hook
 (the documentation says it will not be called more than 10 times a second
 so long as no input is given; so for my example I made the short a char to
 not spam the terminal) and that rl_done being set in the rl_event_hook hook
 will cause readline() to return, but those differences were less
 significant/could be overcome in other ways for my usage (ie, the rate was
 unimportant, just that it's called at all, and rl_done behavior can be
 achieved by setting rl_event_hook to NULL; but just mentioning).
 
 On Thu, Jan 9, 2025, 1:30=E2=80=AFPM Christos Zoulas via gnats <
 gnats-admin%netbsd.org@localhost> wrote:
 
 > The following reply was made to PR lib/58955; it has been noted by GNATS.
 >
 > From: Christos Zoulas <christos%zoulas.com@localhost>
 > To: gnats-bugs%netbsd.org@localhost
 > Cc: lib-bug-people%netbsd.org@localhost,
 >  gnats-admin%netbsd.org@localhost,
 >  netbsd-bugs%netbsd.org@localhost
 > Subject: Re: lib/58955: libedit: rl_event_hook not called when output is
 > piped
 >  to another process
 > Date: Thu, 9 Jan 2025 16:25:16 -0500
 >
 >  --Apple-Mail=3D_2E891251-9880-4BC2-8546-5DC03EA3B102
 >  Content-Transfer-Encoding: quoted-printable
 >  Content-Type: text/plain;
 >         charset=3Dus-ascii
 >
 >  I am not sure. How does readline behave? If it works for non-interactive=
  =3D
 >  processes we should change our code.
 >
 >  Best,
 >
 >  christos=3D
 >
 >  --Apple-Mail=3D_2E891251-9880-4BC2-8546-5DC03EA3B102
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 >
 
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 <div dir=3D"auto"><div>From my tests, readline works the same for interacti=
 ve and non-interactive processes. Just changing the example code to use &qu=
 ot;#include &lt;readline/readline.h&gt;&quot; and linking against GNU readl=
 ine, rl_event_hook is called periodically in either case.</div><div dir=3D"=
 auto"><br></div><div dir=3D"auto">It&#39;s worth noting that GNU readline d=
 oes rate limit calling rl_event_hook (the documentation says it will not be=
  called more than 10 times a second so long as no input is given; so for my=
  example I made the short a char to not spam the terminal) and that rl_done=
  being set in the rl_event_hook hook will cause readline() to return, but t=
 hose differences were less significant/could be overcome in other ways for =
 my usage (ie, the rate was unimportant, just that it&#39;s called at all, a=
 nd rl_done behavior can be achieved by setting rl_event_hook to NULL; but j=
 ust mentioning).<br><br><div class=3D"gmail_quote gmail_quote_container" di=
 r=3D"auto"><div dir=3D"ltr" class=3D"gmail_attr">On Thu, Jan 9, 2025, 1:30=
 =E2=80=AFPM Christos Zoulas via gnats &lt;<a href=3D"mailto:gnats-admin@net=
 bsd.org">gnats-admin%netbsd.org@localhost</a>&gt; wrote:<br></div><blockquote class=
 =3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padd=
 ing-left:1ex">The following reply was made to PR lib/58955; it has been not=
 ed by GNATS.<br>
 <br>
 From: Christos Zoulas &lt;<a href=3D"mailto:christos%zoulas.com@localhost"; target=3D"=
 _blank" rel=3D"noreferrer">christos%zoulas.com@localhost</a>&gt;<br>
 To: <a href=3D"mailto:gnats-bugs%netbsd.org@localhost"; target=3D"_blank" rel=3D"noref=
 errer">gnats-bugs%netbsd.org@localhost</a><br>
 Cc: <a href=3D"mailto:lib-bug-people%netbsd.org@localhost"; target=3D"_blank" rel=3D"n=
 oreferrer">lib-bug-people%netbsd.org@localhost</a>,<br>
 =C2=A0<a href=3D"mailto:gnats-admin%netbsd.org@localhost"; target=3D"_blank" rel=3D"no=
 referrer">gnats-admin%netbsd.org@localhost</a>,<br>
 =C2=A0<a href=3D"mailto:netbsd-bugs%netbsd.org@localhost"; target=3D"_blank" rel=3D"no=
 referrer">netbsd-bugs%netbsd.org@localhost</a><br>
 Subject: Re: lib/58955: libedit: rl_event_hook not called when output is pi=
 ped<br>
 =C2=A0to another process<br>
 Date: Thu, 9 Jan 2025 16:25:16 -0500<br>
 <br>
 =C2=A0--Apple-Mail=3D_2E891251-9880-4BC2-8546-5DC03EA3B102<br>
 =C2=A0Content-Transfer-Encoding: quoted-printable<br>
 =C2=A0Content-Type: text/plain;<br>
 =C2=A0 =C2=A0 =C2=A0 =C2=A0 charset=3Dus-ascii<br>
 <br>
 =C2=A0I am not sure. How does readline behave? If it works for non-interact=
 ive =3D<br>
 =C2=A0processes we should change our code.<br>
 <br>
 =C2=A0Best,<br>
 <br>
 =C2=A0christos=3D<br>
 <br>
 =C2=A0--Apple-Mail=3D_2E891251-9880-4BC2-8546-5DC03EA3B102<br>
 =C2=A0Content-Transfer-Encoding: 7bit<br>
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 =C2=A0Content-Type: application/pgp-signature;<br>
 =C2=A0 =C2=A0 =C2=A0 =C2=A0 name=3Dsignature.asc<br>
 =C2=A0Content-Description: Message signed with OpenPGP<br>
 <br>
 =C2=A0-----BEGIN PGP SIGNATURE-----<br>
 =C2=A0Comment: GPGTools - <a href=3D"http://gpgtools.org"; rel=3D"noreferrer=
  noreferrer" target=3D"_blank">http://gpgtools.org</a><br>
 <br>
 =C2=A0iF0EARECAB0WIQS+BJlbqPkO0MDBdsRxESqxbLM7OgUCZ4A+vAAKCRBxESqxbLM7<br>
 =C2=A0OmyVAJ9kyL1JNCO2qjELSRdcwxYkwxX7OgCdEGXop0mfw3JOMvytJv+j9NN1nKg=3D<br=
 >
 =C2=A0=3DnTPK<br>
 =C2=A0-----END PGP SIGNATURE-----<br>
 <br>
 =C2=A0--Apple-Mail=3D_2E891251-9880-4BC2-8546-5DC03EA3B102--<br>
 <br>
 </blockquote></div></div></div>
 
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