I am running VSCode in Ubuntu to debug a C++ program. Debugging a console app with GDB is working fine except I really want to capture the console log output to a file. I cannot see a way or option to do this. Is there any option to capture this console log output?
Since there does not seem to be a native feature to save the output of a VSCode terminal, maybe you can use in said terminal a command allowing you to save that session.
See for instance "Gdb print to file instead of stdout"
gdb core.3599 -ex bt -ex quit |& tee backtrace.log
As mentioned, the output is written to backtrace.log and also on the screen.
As the OP Andy Tomlin mentions in the comments, this is not compatible with a debugger session.
We solved the problem by just handling it inside the app and redirecting cout internally to a file.
Related
I am using gdb 7.7.1 on ubuntu, GNU gdb (Ubuntu 7.7.1-0ubuntu5~14.04.2) 7.7.1.
My terminal is Konsole 2.13.2.
The problem I am having is, when I go to the TUI mode, after one or two debugger sessions - session, I mean, set breakpoint, run, step over a while and finally kill it by "kill" command - the output starts messed up. Supposedly each output should go to a new line, but now they just all scramble, one immediately after another one.
I attach a screenshot.
I have to quit GDB, open a new terminal tab and start gdb again.
I tried "ctrl-x-a" back and forth, does not help; neither does "ctrl-l".
A while back, I was using another terminal, it also had this problem.
Any help is appreciated.
It appears that your tty settings changed, in much the same way that tty -onlcr might change them (tty onlcr restores the default). Perhaps the code you're debugging changes tty settings, and doesn't get a chance to restore them because of a crash.
As suggested in a comment, using a separate window might provide a workaround.
I'm not very into unix/linux, I'm using rhat linux with sh, tcsh shells.
What I'm trying to do is to debug lifecycle of the object of the class by breaking on it's default, copy c-tors, on d-tor and on operator=; move operations are not defined neither by compiler or me. I break on these functions and printf some lines and also print backtrace
br /project/src/some_file.c:408
commands
silent
printf "<%p> D E F A U L T c-tor bt:\n", this
bt
cont
end
The thing is there're a lot objects of this class, so there is a lot of output, and nothing helps me to disable output to the terminal, so I want see gdb output only in the file, not in the shell. Is it possible to achieve using sh or tcsh? - I can't really impact on the environment and use some other debugger or shell. The reason I want to disable any output from gdb and process being debugged to the shell is because I believe it slows down gdb and execution of the debugged process, which breaks behavior of debugged application.
Using gdb 8.1. I tried logging options of gdb, redirecting output by
run > somefile
and I tried to run gdb like this
gdb -p 1000 -x breakpoint.txt | tee somefile.txt
Thanks many times!
this link has various option for logging
http://sourceware.org/gdb/onlinedocs/gdb/Logging-Output.html
simple one is
set logging file file
Change the name of the current logfile. The default logfile is gdb.txt.
then
set logging on
Enable logging.
A while ago I changed my personal operating system to linux and my development enviroment to KDevelop.
However debugging c++ projects is still not working as it should.
My KDevelop version is 4.2.2 (I installed it through package management)
Every time I hit the "debug button" the application is starting with the console message
warning: GDB: Failed to set controlling terminal: Operation not permitted and debugging functionality is not available.
Any ideas welcome.
(If you need additional information don't hesitate to ask)
I also had this problem, but I use gdb in KDevelop sparsely enough that hadn't bothered me yet. Here's my log of trying to fix it:
Grepping through the GDB 7.3.1 source code reveals that this message is printed when GDB tries to set its master TTY to a newly-created pseudo-tty (see gdb/inflow.c, lines 683-740). In particular, a call to ioctl with request TIOCSCTTY fails with a permissions error.
With this in mind, I took a look at the Linux kernel source code to see what could cause a failure. A bit of searching shows that it will eventually degenerate into a call to tiocsctty(). The comment from tiocsctty that is important here:
/*
* The process must be a session leader and
* not have a controlling tty already.
*/
Since the only other reason it can fail with EPERM is if the tty that GDB creates is actually a controlling tty for another process (which seems highly unlikely), I thought it reasonable to assume that GDB is not a session leader. Fair enough, it's launched by KDevelop after all!
So: I tried not launching the GDB session in an external terminal, and it works. Problem narrowed down.
Originally, the external terminal line was set to konsole --noclose --workdir %workdir -e %exe. Changing this to terminator -e %exe made a slight difference: KDevelop warned me that
GDB cannot use the tty* or pty* devices.
Check the settings on /dev/tty* and /dev/pty*
As root you may need to "chmod ug+rw" tty* and pty* devices and/or add the user to the tty group using "usermod -G tty username".
I checked my permissions; my user was part of the tty group and all relevant files were readable and writable.
Grepping through the KDevelop source code reveals how KDevelop actually sets up the terminal. It runs the shell script
tty > FIFO_PATH ; trap "" INT QUIT TSTP ; exec<&-; exec>&-; while :; do sleep 3600;done
and then sets up GDB to use the terminal device it reads from FIFO_PATH. (My name, by the way, not the one that KDevelop uses.) The problem (as best I can tell) is that gdb is not launched as a child of the shell script, and thus cannot use it as its main tty.
I'm not feeling up to patching KDevelop to make this work properly as of yet (or finding what actually caused this to stop working in the first place . . .), so the best I can suggest at the moment is to simply not use an external terminal for debugging purposes.
Good luck! I'll update if I find anything useful.
As Arthur Zennig said, for more information, you need to do something
Firstly, you need to create the Terminal profile
Secondly, open Launch Configurations, fill info such as the image below
Good luck!
In case you got the error:
"Can't receive konsole tty/pty. Check that konsole is actually a
terminal and that it accepts these arguments"
RUN > CONFIGURE LAUCHERS > (See picture below. My project name was "loops")
What worked for me was to uncheck checkbox "Use External Terminal". Found the in the "Compiled Binaries" Tab.
I'm trying to get gdb to run programs with input redirection to stdin. For example, without gdb I would run a program like this:
prog < input.txt
Now in gdb, the usual way to do this is run < input.txt. However, it doesn't work for me and when doing this nothing gets redirected into stdin.
I'm using Windows with MinGW. What could be the problem?
As far back as the late '90s, broken command line redirection was a known and assumed limitation. My suspicion is that it remains that way, since the mingw32 port of gdb still gleefully passes on verbatim all run arguments (including redirects) to the debugee.
Several possible workarounds:
if you have the option to alter the command line interface, then implement bbadour's suggestion
otherwise, if you can easily suspend the process before the point you want to debug at, invoke the debugee (with redirection) from a shell and attach to it while it is already running
otherwise, if you have symbols for the debugee (gcc -g) or you know the address of main() (gcc -Wl,-Map,mapfile) and can set a breakpoint there, proceed in the following manner (tested with mingw gdb 6.8.0):
# gdb debugee.exe
(gdb) b main
(gdb) run non-redirect-arguments-if-any
(gdb) p dup2(open("/tmp/input.txt", 0), 0)
(gdb) c
I ran into the same issue here, and I just got into the habit of adding a command-line argument to allow grabbing input from a file.
e.g. Parsing a "-i ifile" argument using argc and argv to get input from ifile instead of stdin and parsing a "-o ofile" to write output to ofile instead of stdout.
Then I just use those arguments instead of redirects.
The tools that come with MinGW often are not the latest versions and often have features omitted. ::shrug::
Input redirection is supported starting with GDB 8.0. From the NEWS file:
Native debugging on MS-Windows supports command-line redirection
Command-line arguments used for starting programs on MS-Windows
can now include redirection symbols supported by native Windows
shells, such as '<', '>', '>>', '2>&1', etc. This affects GDB
commands such as "run", "start", and "set args", as well as the
corresponding MI features.
In bash, I can use the script command, which dumps everything that shows on the shell to a file, including:
commands typed
PS1 line
stdout and stderr of commands
What is the equivalent in gdb?
I tried to run shell script from inside GDB, but after I hit return, I was in the shell and lost the shell prompt and could not run command any more. Moreover I could not use ctrl+c or ctrl+\ to exit. I needed to force kill the /bin/login tty2 to exit.
If you want to log GDB's output, you can use the GDB logging output commands, eg.
set logging file mylog.txt
set logging on
If you want to redirect your program's output to a file, you can use a redirect, eg.
run myprog > mylog.txt
see the chapter on program IO in the GDB manual for more information
Create a text file, i.e. gdbCommands.txt, with the following commands
set logging on my_log_file\nbt 10\nq
bt 10, indicates the number of lines (function calls) we need from the backtrace, in our example is 10 lines.
Execute gdb using the following command, assuming a core dump file core.2345
gdb -x gdbCommands.txt myApp core.2345
Open my_log_file and inspect backtrace!
howto-redirect-gdb-backtrace-output-to-a-text-file
I have logging enabled using:
set trace-commands on
set pagination off
set logging file $log
and show logging reports (to both to terminal and file):
+show logging
Currently logging to mylog.
Logs will be appended to the log file.
Output will be logged and displayed
If I print the value of a variable that also gets logged (to both to terminal and file):
+p myvar
$2 = 0
But if I do command like where or “info b” all I get logged to the file is:
+where
+info b
Anyone know why or how to fix it?
Have a look at the GDB documentation. Search for "Canned Sequences of Commands". There is a way to save GDB commands in a file and run them with the source command and you can use some GDB commands in these scripts to print information available to GDB (like echo, output and printf).
If you want that output in a file, use set logging file FILE.