A program compiled with arm-linux-gnueabi-gcc -g3 main.c .
$ gdb a.out
$ l
$ main.c: No such file or directory.
It is unable to display program lines with line number. let me know If i am missing something ?
However I am able to run program , with run command even backtrace I am able to get.
My issue is same as gdb can not load source file?
but , GDB version 7.8.
GDB needs source code to be present on same machine as in where binary been run.
mine was cross compilation , I was running program on different host . That's why I had that issue.
Related
my coredump file is produced by the shell command sudo spawn-fcgi fcgi-bin -a 0.0.0.0 -p 8089 &, fcgi-bin is compiled by the c++ command g++ -g fcgiMain.cpp fcgiEnv.cpp -o fcgi-bin etc. to deploy with nginx ,as we know that debug coredump file with the command gdb ./test_bin test_coredump,but now i have two bin program spawn-fcgi and "fcgi-bin",if i use the command gdb ./spawn-fcgi coredump and bt to look at the stack ,then it will look like this picture
so anybody can tell me how to deal with this coredump file ,thanks a lot!
There are two separate executables at play here: spawn-fcgi and fcgi-bin. The former execs the latter.
In the GDB output, you can see that the core was produced by fcgi-bin. Therefore, that's the executable you want to give to GDB:
gdb fcgi-bin coredump
I just switched to ubuntu and I wanted to setup notepad++ for CPP.
So I used the NppExec plugin to compile within notepad++,
My script was :
npp_save
g++ "$(FULL_CURRENT_PATH)" -o "$(CURRENT_DIRECTORY)\$(NAME_PART)obj"
./"$(NAME_PART)obj"
Here the "obj" I used is to just save the file with an "obj" keyword nothing else.
The last line ./"$(NAME_PART)obj" is to run the program.
But it looks not working in ubuntu, it produces this error:
NPP_SAVE: Z:\home\username\cpp\test.cpp
g++ "Z:\home\username\cpp\test.cpp" -o "Z:\home\username\cpp\testobj"
; about to start a child process: "g++ "Z:\home\username\cpp\test.cpp" -o "Z:\home\username\cpp\testobj"
CreatProcess() failed with error code 2:
File not found.
./"testobj"
; about to start a child process: "./"testobj""
CreatProcess() failed with error code 2:
File not found.
I have investigated some of what I think is the problem, so I think is the usage of / and \ in changing the directory.
I don't know how to fix that, so I can not be sure.
Any ideas? :) I am using vim btw in the same machine and it is working perfectly.
In theory it might be possible (see below), in practice it is rather convoluted and works only for simple compiles (like single file hello world type).
I would suggest you try a linux program, e.g.
an editor like
scite (same editing engine as notepad++) or
kate
or a real IDE like
kdeveloper or
qtcreator.
The problems with Notepad++ inside wine and g++ outside wine (from the linux install ) are this:
notepad++ inside wine under linux is still a windows program
NppExec can only do, what a cmd inside wine can do.
starting g++ directly inside cmd is an error due to g++ being a linux binary and not a windows binary
that is your CreatProcess() failed with error code 2, it means: you are trying to execute a linux program inside wine.
That does not work! (At least not so easy.)
Though you can start linux program inside cmd inside wine using start /unix ...
started this way, g++ wants linux paths and NppExec through its variables will provide only windows paths (whatever wine has set up as drives like Z:\home\username\src\hello.cpp)
though you can convert wine paths to linux paths via the winepath -u command.
g++ started through 'start /unix ... ' inside a cmd inside wine has no proper terminal to report errors to you
though you can start an xterm for g++ and have g++ reports its messages to the xterm
the downside is that g++ will report errors using the linux paths in the xterm, so you cannot double click on an error message an get to the corresponding filename and line.
You get the idea: its complicated not comfortable.
What worked for me for a helloword.cpp was this NppExec script:
NPP_SAVE
npp_run cmd /c start /unix /usr/bin/xterm -e "/usr/bin/winepath -u '$(FULL_CURRENT_PATH)' | xargs g++ -o /tmp/a.out && /tmp/a.out ; echo 'Press return'; read"
The second line
uses an xterm,
let winepath convert the Z:\home\... path to /home/... and
have that send to g++ for compilation using /tmp/a.out as binary
if compile is successfull, /tmp/a.out is executed
the echo and read are for keeping the xterm open so that you can read the output.
If you really want to use Notepad++ inside wine, one option might be using Gnu Make outside of wine and have NppExec run make all or make run similar to the g++ in my script example. That would work for more complicated compiles.
I'm currently running a file manager program that abruptly crashed with a segmentation fault and dumped a core file. So I used gdb to debug the core file as:
gdb /path/to/executable /path/to/core
The program which I was running is written in C++. When I ran GDB and tried to print the source lines using "list", I got the following error:
(gdb) bt
#0 0x0000000000554286 in
MyFSEventManager::AddEvent(wxFileSystemWatcherEvent&) ()
#1 0x00000000005ab2e8 in
MyGenericDirCtrl::OnFileWatcherEvent(wxFileSystemWatcherEvent&) ()
(gdb) f 0
#0 0x0000000000554286 in
MyFSEventManager::AddEvent(wxFileSystemWatcherEvent&) ()
(gdb) l
1 /build/glib2.0-prJhLS/glib2.0-2.48.2/./glib/gmain.c: No such file or directory.
Why does gdb say this "/build/glib2.0-prJhLS/glib2.0-2.48.2/./glib/gmain.c: No such file or directory." I do not hit this issue with some other programs that I've debugged using gdb.
The operating system used is Ubuntu 16.04 running on Oracle virtual box. I think may be the gdb symbols were not loaded. I'm not sure why since I compiled the program using the "-g" option. I really need to know the source lines where the code crashes via gdb.
Any suggestions?
EDIT: changes after suggestions from Employed Russian
I was compiling my main using "-g" option and linking it to "existing" object files which were obviously not compiled using "-g" so when the core dumped, I could not see the source for these files. So I went ahead and recompiled those files with "-g" option and reproduced the core dump. It's able to show me the source lines now.
Why does gdb say this "/build/glib2.0-prJhLS/glib2.0-2.48.2/./glib/gmain.c: No such file or directory."
Because you really don't have that file on your system.
I think may be the gdb symbols were not loaded
GDB did load debug symbols for glib, but not for your main executable.
I'm not sure why since I compiled the program using the "-g" option.
Since we don't have your compile and link lines, we can't tell exactly what's wrong, but some of the common issues are:
You have a "stray" -s or -Wl,-s on your link line (this strips debug info from the resulting binary).
You have -g when compiling your main.c, but not when compiling the source in which MyFSEventManager::AddEvent() is defined
P.S.
(gdb) bt
This doesn't seem to be the complete output from bt command. Always try to paste complete outputs as it makes helping easier :)
I have a file called test. Even after compiling it with -g, when I run it in gdb, it says no debugging symbols found. I have also tried using -ggdb but it too was off no use. Please help.
Output for : gdb test
This GDB was configured as "x86_64-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/bin/test...(no debugging symbols found)...done.
The issue is that you are attempting to debug the wrong program.
Your program is called test and yet you are debugging /usr/bin/test (a system program that will almost certainly be shipped without symbols; even if it did contain symbols, they wouldn't relate to your source code).
gdb will search $PATH to find the executable. From here:
exec-file [ filename ] Specify that the program to be run (but not the
symbol table) is found in filename. gdb searches the environment
variable PATH if necessary to locate your program. Omitting filename
means to discard information on the executable file.
Try using the command:
$ gdb ./test
Remove a.out and then try again. It worked for me as I was also getting the same error.
rm a.out
gcc -g your_code.c
Check that the executable is not stripped, you can see that with file /usr/bin/test
GDB is not showing me the line source after next/stop , and displays only line number and source file , like this :
(gdb) n
7 in test/test.c
whereas I expect it to display the current line , like this :
(gdb) next
17 char * good_message = "Hello, world.";
any settings in .gdbinit that might help me do this ?
whereas I expect it to display the current line , like this
On many platforms, such as ELF, the compiler records both the path to the source (test/test.c in your case), and the compilation directory, allowing GDB to display source regardless of which directory you invoke it in.
But many platforms are less flexible, and don't have a place to record compilation directory. On such platforms (e.g. AIX), you must either start GDB in the compilation directory, or tell it where to look for sources with directory command.
Probably my answer may not be a perfect solution but the way you compile your source program matters. For example in my case if you do g++ fib.cpp -o fib and then try to run gdb fib it won't print the source code with list. Using debug flag g++ -g fib.cpp -o fib and then running with gdb solved my problem.