X-Recipient: archive-cygwin@delorie.com X-SWARE-Spam-Status: No, hits=0.8 required=5.0 tests=BAYES_40,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SARE_MSGID_LONG45,T_TO_NO_BRKTS_FREEMAIL X-Spam-Check-By: sourceware.org MIME-Version: 1.0 In-Reply-To: <20100410181700.GA7321@ednor.casa.cgf.cx> References: <20100410140811.GA8593@ednor.casa.cgf.cx> <20100410161626.GA1904@ednor.casa.cgf.cx> <20100410173607.GA3986@ednor.casa.cgf.cx> <20100410181700.GA7321@ednor.casa.cgf.cx> Date: Sat, 10 Apr 2010 22:09:32 +0100 Received: by 10.239.164.134 with SMTP id t6mr167138hbd.2.1270933772322; Sat, 10 Apr 2010 14:09:32 -0700 (PDT) Message-ID: Subject: Re: 1.7.3: Backspace key not working in GNU screen. From: Andy Koppe To: cygwin@cygwin.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-IsSubscribed: yes Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Delivered-To: mailing list cygwin@cygwin.com Christopher Faylor wrote: > I'm not 100% sure that this is the right fix but the new snapshot at > least works around the problem. Thanks. > The problem is that screen explicitly sets VERASE to 0. =C2=A0I believe t= hat > it does that to mean "there is really no erase character since I'm > handling that". You're right. Zero is the value of the _POSIX_VDISABLE constant for disabling special characters. Therefore, using c_cc[VERASE] as the backspace keycode was a bad idea all along. Sorry for suggesting it in the first place. > That should not cause Cygwin to send a null character. > I think it should probably just send the default \177 character. Makes sense given the botched design, but of course it does mean that the user's backspace keycode setting is ignored. Also, 'screen' would be expecting what was set in c_cc[VERASE] as the backspace keycode. I can think of two ways to fix the design. One would be to introduce a CYGWIN flag for switching from the default ^? to ^H, named something like 'backspace_sends_bs', 'legacy_bs' or 'bs_is_ctrl_h'. Another would be to implement the DECBKM ("DEC Backarrow Key Mode") control sequence for the purpose, which is also supported by xterm and mintty: \e[?67h Backspace key sends ^H \e[?67l Backspace key sends ^? Andy -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple