From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 100835 invoked by alias); 15 Mar 2019 15:38:21 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 100825 invoked by uid 89); 15 Mar 2019 15:38:21 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-4.0 required=5.0 tests=AWL,BAYES_00,SPF_PASS autolearn=ham version=3.3.1 spammy=HX-Languages-Length:1480, displays, explain X-HELO: eggs.gnu.org Received: from eggs.gnu.org (HELO eggs.gnu.org) (209.51.188.92) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 15 Mar 2019 15:38:19 +0000 Received: from fencepost.gnu.org ([2001:470:142:3::e]:42594) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h4ouX-0008OY-Sq; Fri, 15 Mar 2019 11:38:18 -0400 Received: from [176.228.60.248] (port=2456 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1h4ouX-0000TY-Bo; Fri, 15 Mar 2019 11:38:17 -0400 Date: Fri, 15 Mar 2019 15:38:00 -0000 Message-Id: <83tvg4ywq2.fsf@gnu.org> From: Eli Zaretskii To: Pedro Alves CC: tromey@adacore.com, gdb-patches@sourceware.org In-reply-to: (message from Pedro Alves on Fri, 15 Mar 2019 14:15:23 +0000) Subject: Re: [PATCH v2] Fix first time you type UP or DOWN in TUI's command window (Re: [RFC 8.3 0/3] Some style fixes) References: <20190308210433.32683-1-tromey@adacore.com> <83pnr08tc8.fsf@gnu.org> <83zhq26fcw.fsf@gnu.org> <874l899nh3.fsf@tromey.com> <8336ns3uv4.fsf@gnu.org> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-IsSubscribed: yes X-SW-Source: 2019-03/txt/msg00317.txt.bz2 > Cc: gdb-patches@sourceware.org > From: Pedro Alves > Date: Fri, 15 Mar 2019 14:15:23 +0000 > > Bingo. > > So I think this is the right fix: > > >From 781ed3b6d82a4fb54f7bfe59185f0e6e9efd6b59 Mon Sep 17 00:00:00 2001 > From: Pedro Alves > Date: Fri, 15 Mar 2019 13:05:26 +0000 > Subject: [PATCH] Fix first time you type UP or DOWN in TUI's command window > > The first time you type UP or DOWN arrow in the command window, GDB > should scroll the source window, but instead it displays the line > number and the file name in the command window(?). > > What happens there is that the first time we call > tui_ui_out::do_field_int, it doesn't initialize m_line, because > m_start_of_line is -1, as set by the constructor; and then the > following call to tui_ui_out::do_field_string falls back to > cli_ui_out::do_field_string because m_line is zero. > > The problem is caused by a typo in the C++ification of tui_ui_out, > commit 112e8700a6f, where m_line and m_start_of_line's initial values > were swapped from what they used to be: Thanks, this sound right to me. Still, I'd welcome some comments in the header which explain the semantics of non-positive values of these members, and for m_start_of_line, also its role in general. Fixing this bug could have been much easier if that information was available to begin with.