wh command without argument to gdb in Emacs shell buffer
Running gdb in Emacs's shell-mode buffer and then issueing wh
without argument by mistake causes GDB to get hung (without no visible
activity) [or rathr print long blank lines without prompt!?]
I am perplexed as to what is going on as I uncover a few things along
the way.
Below, a log is excerpted.
---
Note 1: I am NOT using Emacs's gdb-mode when this happens. I type
gdb as an ordinary shell command within the Emacs's shell buffer.
Note 2: Background.
In the old days, wh would be considered a shorthand for where
command. But today there is winheight command and wh is regarded
as a shorthand for it. An old timer like me types wh as a shorthand
for where without argument, and noticed this strange problem.
After a few days of pondering and trying to fix various issues like
missing shared library symbols, etc., finally I got curious and typed
help wh and found out about this winheight command. So I was
typing winheight command instead of where all along.
Note 3: If I use gdb in an ordinary terminal screen, say, without
argument and type wh to gdb prompt,
$ gdb
gdb wh
I get a small popup window, and in this case, it says, No source
available
and the usage help is printed to the original tty console where gdb
prompt appears, and prompt returns.
[I mistook this popup window as a X window, but no, it seems
it is a text rectangle created by termcap library or similar! This is
a source of confusion on my analysis. This confusion is in this writeup.]
That is good.
In emacs's shell-buffer usage, there is no indication of either (no
window, no help message to the prompt. Well, control-C does not seem
to work, but please read the excerpt log #2 at the end.)
To wit, here is the log from within Emacs's shell buffer.
The first run of gdb simply prints the help message for wh and quits.
The second run gets hung after I type wh.
[Ugh! No, as I write this message, I got still wiser and hit C-MC-J to
this seemingly hung gdb and I got gdb prompt again. What is going
on? More in the Log #2 at the end.]
Log 1:
--- begin quote ---
ishikawa@debian-vbox-ci:/home/ishikawa$ gdb
GNU gdb (GDB) 7.6.2 (Debian 7.6.2-1)
Copyright (C) 2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later http://gnu.org/licenses/gpl.html
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type show copying
and show warranty for details.
This GDB was configured as i486-linux-gnu.
For bug reporting instructions, please see:
http://www.gnu.org/software/gdb/bugs/.
(gdb) help wh
Set the height of a specified window.
Usage: winheight win_name [+ | -] #lines
Window names are:
src : the source window
cmd : the command window
asm : the disassembly window
regs : the register display
(gdb) quit
ishikawa@debian-vbox-ci:/home/ishikawa$ gdb
GNU gdb (GDB) 7.6.2 (Debian 7.6.2-1)
Copyright (C) 2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later http://gnu.org/licenses/gpl.html
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type show copying
and show warranty for details.
This GDB was configured as i486-linux-gnu.
For bug reporting instructions, please see:
http://www.gnu.org/software/gdb/bugs/.
(gdb) wh
---
As you can see, control-C won't interrupt gdb.
I have to kill gdb from another console.
[But please read the log #2 excerpt at the end. It seems that there is
another process running in a mixed manner in this terminal.]
This is a major usability issue.
Merely typing a command without an argument should not
render gdb unusable.
Yes, I think emacs might be setting up a strange environment for
gdb, but gdb code should be ready for failing to open a X window,
etc.
TIA
My Environment:
gdb --version
GNU gdb (GDB) 7.6.2 (Debian 7.6.2-1)
Copyright (C) 2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later http://gnu.org/licenses/gpl.html
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type show copying
and show warranty for details.
This GDB was configured as i486-linux-gnu.
For bug reporting instructions, please see:
http://www.gnu.org/software/gdb/bugs/.
ishikawa@debian-vbox-ci:/home/ishikawa$ emacs --version
GNU Emacs 24.4.1
Copyright (C) 2014 Free Software Foundation, Inc.
GNU Emacs comes with ABSOLUTELY NO WARRANTY.
You may redistribute copies of Emacs
under the terms of the GNU General Public License.
For more information about these matters, see the file named COPYING.
ishikawa@debian-vbox-ci:/home/ishikawa$ uname -a
Linux debian-vbox-ci 3.2.0-4-686-pae #1 SMP Debian 3.2.57-3+deb7u2 i686
GNU/Linux
OS Issue:
The particular log was obtained
