GNU bug report logs - #1490
23.0.60; C-d sends "\n" while debugging with gdb in Emacs

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Message #5 received at submit <at> emacsbugs.donarmstrong.com (full text, mbox):

From: "Joseph Yen" <joseph.yen <at> gmail.com>
To: emacs-pretest-bug <at> gnu.org
Cc: rfrancoise <at> debian.org
Subject: 23.0.60; C-d sends "\n" while debugging with gdb in Emacs
Date: Thu, 4 Dec 2008 22:21:49 +0800

While in the gdb of Emacs ...
  (gdb) set var retp = fgets(buf, 32, stdin)
                                          <--- I typed C-d here
without typing RETURN
  (gdb) p retp
  $4 = 0xffe1e58c "\n"
  (gdb) set var reti = getchar()
                                          <--- I typed C-d here
without typing RETURN
  (gdb) p reti
  $6 = 10

But in pure gdb
  (gdb) set var retp = fgets(buf, 32, stdin)
  (gdb) p retp
  $1 = 0x0
  (gdb) set var reti = getchar()
  (gdb) p reti
  $2 = -1
  (gdb)

Emacs sends extra '\n' character when i type C-d in debugger mode


In GNU Emacs 23.0.60.1 (i486-pc-linux-gnu, GTK+ Version 2.12.11)
 of 2008-11-30 on elegiac, modified by Debian
 (emacs-snapshot package, version 1:20081129-1)
configured using `configure  '--build' 'i486-linux-gnu' '--host'
'i486-linux-gnu' '--prefix=/usr' '--sharedstatedir=/var/lib'
'--libexecdir=/usr/lib' '--localstatedir=/var' '--\
infodir=/usr/share/info' '--mandir=/usr/share/man' '--with-pop=yes'
'--enable-locallisppath=/etc/emacs-snapshot:/etc/emacs:/usr/local/share/emacs/23.0.60/site-lisp:/usr/local/s\
hare/emacs/site-lisp:/usr/share/emacs/23.0.60/site-lisp:/usr/share/emacs/site-lisp'
'--with-x=yes' '--with-x-toolkit=gtk' 'build_alias=i486-linux-gnu'
'host_alias=i486-linux-gn\
u' 'CFLAGS=-DDEBIAN -DSITELOAD_PURESIZE_EXTRA=5000 -g -O2' 'LDFLAGS=-g
-Wl,--as-needed' 'CPPFLAGS=''
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t
Major mode: Debugger
Minor modes in effect:
  show-paren-mode: t
  tooltip-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t


--
joseph.yen <at> gmail.com

Message #10 received at 1490 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: "richardeng" <richardeng <at> foxmail.com>
To: "Joseph Yen" <joseph.yen <at> gmail.com>,
        "1490" <1490 <at> debbugs.gnu.org>
Subject: Re: bug#1490: 23.0.60; C-d sends "\n" while debugging with gdb in Emacs
Date: Fri, 5 Dec 2008 11:25:20 +0800

Package: emacs
Version: 23.0.60
Severity: minor
Tags: patch

--- gdb-ui.el.~1.253.~  2008-07-16 16:02:52.000000000 -0700                                                    
+++ gdb-ui.el   2008-11-03 03:51:32.000000000 -0800                                                            
@@ -1248,7 +1248,9 @@
            (remove-text-properties (point-min) (point-max) '(face))))                                         
        (if gud-running                                                                                        
            (progn                                                                                             
-             (let ((item (concat string "\n")))                                                               
+             (let ((item ""))                                                                                 
+               (unless (equal string "")                                                                      
+                 (setq item (concat string "\n")))                                                            
                (if gdb-enable-debug (push (cons 'send item) gdb-debug-log))                                   
                (process-send-string proc item)))                                                              
          (if (string-match "\\\\\\'" string)      

Message #15 received at 1490 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Chong Yidong <cyd <at> stupidchicken.com>
To: Nick Roberts  <nickrob <at> snap.net.nz>
Cc: 1490 <at> debbugs.gnu.org
Subject: Re: Re: bug#1490: 23.0.60; C-d sends "\n" while debugging with gdb in Emacs
Date: Thu, 16 Apr 2009 00:23:34 -0400

Hi Nick,

Could you review the patch in Bug#1490?  Thanks.

http://debbugs.gnu.org/cgi/bugreport.cgi?bug=1490

Message #20 received at 1490 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: nickrob <at> snap.net.nz (Nick Roberts)
To: Chong Yidong <cyd <at> stupidchicken.com>
Cc: 1490 <at> debbugs.gnu.org
Subject: Re: Re: bug#1490: 23.0.60; C-d sends "\n" while debugging with gdb in Emacs
Date: Thu, 16 Apr 2009 21:15:24 +1200

I can't begin to imagine where one would do something like:

  (gdb) set var retp = fgets(buf, 32, stdin)

in GDB.  If I do this from the command line I get:

  Program received signal SIGSEGV, Segmentation fault.
  0x00007ffff7852522 in fgets () from /lib/libc.so.6
  0x00007ffff7852522 <fgets+50>:	mov    (%rdx),%eax
  ...

I can get

  (gdb) set var reti = getchar()

to work as described.  The proposed patch might be the right thing to do but,
unless Joseph Yen can give a compelling reason as to why someone would
generally type something like this, I intend to leave it as it is until after
the release as I am unsure whether it will have unintended side effects.

-- 
Nick

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