bug#70014: 29.2; debugging with gdb problem with input/output buffer

bug#70014: 29.2; debugging with gdb problem with input/output buffer

[Davide Lombardo]

When Debugging a simple program with gdb in gdb-many-windows mode,
when I type any kind of input in the I/O dedicated buffer, I always
get the message - Output file descriptor of gdb-inferior is
closed - I can't send input to the program I'm trying to debug, I don't
get any output either.

In GNU Emacs 29.2 (build 2, x86_64-w64-mingw32) of 2024-02-29 built on
  fv-az663-517
Windowing system distributor 'Microsoft Corp.', version 10.0.19045
System Description: Microsoft Windows 10 Pro (v10.0.2009.19045.4170)

Configured using:
  'configure --prefix=/ucrt64 --host=x86_64-w64-mingw32
  --build=x86_64-w64-mingw32 --with-modules --without-dbus
  --without-compress-install --with-tree-sitter
  --with-native-compilation=aot 'CFLAGS=-march=nocona -msahf
  -mtune=generic -O2 -pipe -fstack-protector-strong
  -fno-optimize-sibling-calls' CPPFLAGS=-D__USE_MINGW_ANSI_STDIO=1
  'LDFLAGS=-pipe -lpthread''

Configured features:
ACL GIF GMP GNUTLS HARFBUZZ JPEG JSON LIBXML2 MODULES NATIVE_COMP NOTIFY
W32NOTIFY PDUMPER PNG RSVG SOUND SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS TREE_SITTER WEBP XPM ZLIB

Important settings:
   value of $LC_CTYPE: it_IT.UTF-8
   value of $LANG: ITA
   locale-coding-system: cp1252

Major mode: Inferior I/O

Minor modes in effect:
   gdb-many-windows: t
   shell-dirtrack-mode: t
   server-mode: t
   electric-pair-mode: t
   tooltip-mode: t
   global-eldoc-mode: t
   show-paren-mode: t
   electric-indent-mode: t
   mouse-wheel-mode: t
   tool-bar-mode: t
   menu-bar-mode: t
   file-name-shadow-mode: t
   global-font-lock-mode: t
   font-lock-mode: t
   blink-cursor-mode: t
   line-number-mode: t
   indent-tabs-mode: t
   transient-mark-mode: t
   auto-composition-mode: t
   auto-encryption-mode: t
   auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message yank-media puny dired
dired-loaddefs rfc822 mml mml-sec epa derived epg rfc6068 epg-config
gnus-util mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util
mail-prsvr mail-utils mule-util cus-start cus-load gdb-mi bindat gud
easy-mmode files-x shell pcomplete time-date eglot external-completion
array filenotify jsonrpc ert pp ewoc debug backtrace find-func
flymake-proc flymake thingatpt compile text-property-search comint
ansi-osc ansi-color imenu cc-mode cc-fonts cc-guess cc-menus cc-cmds
cc-styles cc-align cc-engine cc-vars cc-defs comp comp-cstr warnings
icons rx cl-extra help-mode server display-line-numbers elec-pair
company-oddmuse company-keywords company-etags etags fileloop generator
xref project ring company-gtags company-dabbrev-code company-dabbrev
company-files company-clang company-capf company-cmake company-semantic
company-template company-bbdb company pcase info company-autoloads
gnu-elpa-keyring-update-autoloads package browse-url url url-proxy
url-privacy url-expand url-methods url-history url-cookie
generate-lisp-file url-domsuf url-util mailcap url-handlers url-parse
auth-source cl-seq eieio eieio-core cl-macs password-cache json subr-x
map byte-opt gv bytecomp byte-compile url-vars cl-loaddefs cl-lib rmc
iso-transl tooltip cconv eldoc paren electric uniquify ediff-hook
vc-hooks lisp-float-type elisp-mode mwheel dos-w32 ls-lisp disp-table
term/w32-win w32-win w32-vars term/common-win tool-bar dnd fontset image
regexp-opt fringe tabulated-list replace newcomment text-mode lisp-mode
prog-mode register page tab-bar menu-bar rfn-eshadow isearch easymenu
timer select scroll-bar mouse jit-lock font-lock syntax font-core
term/tty-colors frame minibuffer nadvice seq simple cl-generic
indonesian philippine cham georgian utf-8-lang misc-lang vietnamese
tibetan thai tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek
romanian slovak czech european ethiopic indian cyrillic chinese
composite emoji-zwj charscript charprop case-table epa-hook
jka-cmpr-hook help abbrev obarray oclosure cl-preloaded button loaddefs
theme-loaddefs faces cus-face macroexp files window text-properties
overlay sha1 md5 base64 format env code-pages mule custom widget keymap
hashtable-print-readable backquote threads w32notify w32 multi-tty
make-network-process native-compile emacs)

Memory information:
((conses 16 219058 30315)
  (symbols 48 16849 3)
  (strings 32 55181 2851)
  (string-bytes 1 1759188)
  (vectors 16 35566)
  (vector-slots 8 679661 36722)
  (floats 8 108 169)
  (intervals 56 2273 0)
  (buffers 984 28))

bug#70014: 29.2; debugging with gdb problem with input/output buffer

[Eli Zaretskii]

> Date: Tue, 26 Mar 2024 16:15:51 +0100
> From: Davide Lombardo <careless@live.it>
> 
> When Debugging a simple program with gdb in gdb-many-windows mode,
> when I type any kind of input in the I/O dedicated buffer, I always
> get the message - Output file descriptor of gdb-inferior is
> closed - I can't send input to the program I'm trying to debug, I don't
> get any output either.
> 
> In GNU Emacs 29.2 (build 2, x86_64-w64-mingw32) of 2024-02-29 built on
>   fv-az663-517

This feature doesn't work on MS-Windows because the underlying GDB
feature (set inferior-tty) doesn't.  If someone knows how to fix that,
patches are very welcome, but they are are probably need to be
submitted to GDB, not to Emacs.

bug#70014: 29.2; debugging with gdb problem with input/output buffer

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > This feature doesn't work on MS-Windows because the underlying GDB
  > feature (set inferior-tty) doesn't.  If someone knows how to fix that,
  > patches are very welcome, but they are are probably need to be
  > submitted to GDB, not to Emacs.

Emacs should at least five a clear error message.
That it can do without changes in GDB.  For users to know
that this usage is unsupported in GDB would be a big help.

I would guess that there are fundamental reasons it is not supported

-- 
Dr Richard Stallman (https://stallman.org)
Chief GNUisance of the GNU Project (https://gnu.org)
Founder, Free Software Foundation (https://fsf.org)
Internet Hall-of-Famer (https://internethalloffame.org)

bug#70014: 29.2; debugging with gdb problem with input/output buffer

[Eli Zaretskii]

> From: Richard Stallman <rms@gnu.org>
> Cc: careless@live.it, 70014@debbugs.gnu.org
> Date: Thu, 28 Mar 2024 18:03:36 -0400
> 
>   > This feature doesn't work on MS-Windows because the underlying GDB
>   > feature (set inferior-tty) doesn't.  If someone knows how to fix that,
>   > patches are very welcome, but they are are probably need to be
>   > submitted to GDB, not to Emacs.
> 
> Emacs should at least five a clear error message.
> That it can do without changes in GDB.  For users to know
> that this usage is unsupported in GDB would be a big help.

gdb-inferior-io--init-proc silently punts when it cannot get a useful
name from process-tty-name.  It always did that.  This initialization
is done during initialization of the session, where displaying error
messages is tricky at best, and I also don't know what message to
display, TBH.  But patches are welcome.

> I would guess that there are fundamental reasons it is not supported

Yes: Emacs on Windows uses pipes to communicate with subprocesses,
because PTYs don't exist or cannot be used by Emacs.  So there's no
name of a TTY to use in the "set inferior-tty" command.