GDB on eclipse debug mode can't find stdlib/rand.c - c++

I am trying to put the gdb to run with eclipse cdt on ubuntu to start debugging some simple programs. So I did the steps I reckon as necessary to get it running:
1. Create an executable project
2. Compile
3. Run
4. Create the file .gdbinit and place it on the main project folder
5. Set some of the debugger configuration:
5. I also tried to find a .gdbinit file that would look some like this:
set schedule-multiple
dir ~/gcc_build/4.7.2/build/gcc
dir ~/gcc_build/4.7.2/gcc
dir ~/gcc_build/4.7.2/gcc/cp
dir ~/gcc_build/4.7.2/gcc/lto
source ~/gcc_build/4.7.2/build/gcc/gdbinit.in
But I didn't find anything similar in my computer, even after doing a:
# find / -name .gdbinit
So, my file .gdbinit end up with the simple content - yes only that:
set new-console on
Then I clicked on Apply and Debug:
The gdb starts working nicely as expected. I press the button "step over / F6" and the debugger goes jumping through the code step by step. Until the point it reaches the command rand() and the gdb hangs with the message:
Can't find a source file at "/build/buildd/eglibc-2.19/stdlib/rand.c"
Locate the file or edit the source lookup path to include its location.
Thus I also tried unsuccessfully to find the rand.c to update this path to include its location:
# find / -name rand.c
# find / -name stdlib
After the error message from GDB complaining that rand.c is missing, then I tried to keep stepping... since then the stepping mode is disable when I restart the debug:
Is this problem happening because some setting for my file .gdbinit is missing? Or some how GDB is not able to find the rand.c from stdlib from c99? When I compile and run the program it runs nicely. Only when I try to launch the debugger is when GDB crashes.
Update: I got the missing rand.c problem after running the commands:
# apt-get install libc6-dbg
# apt-get source libc6
But now a different error appears:
Can't find a source file at "/build/buildd/eglibc-2.19/csu/libc-start.c"
Locate the file or edit the source lookup path to include its location.
Should I also install that library for gdb?
All suggestions are highly appreciated.

From what I saw on your description... looking to the 4th and 5th image you posted, you did right all the required steps.
However, it seems to me that your GDB is attached to several projects. That means that unless you really need that, I would strongly advise you to select all project that you are not currently debugging and delete them from the debugger mode. So, my suggestion is that after you have done all the steps you did so far, then go on:
Debug Configurations > C/C++ Applications: (drop down it)
... then click on each project you are not compiling, with right button from the mouse select "delete" - but don't worry, it will not delete your project, but only the attachment of that project to your debugger mode.
Then restart the eclipse. When you again try to run in the debugger mode, everything will run much smoother than before.

Step1:
Go to https://www.gnu.org/software/libc/ to download glibc.
Step2:
unzip it locally and whenever the eclipse prompts "Can't find ... xxx.c", just load the file into eclipse. It will work.

Related

gdb tui, dl-debug.c:74 no such file or directory

If I start gdb -tui or gdbtui with an -g flag compiled file, then set b main and press r I get the hint dl-debug.c:74 no such file or directory and the output while stepping through the source window will be written to the source window at the bottom, which also messes up this window so that is not really readable. I've already looked at askubuntu.com and Sourceware Bugzilla – Bug List and at this site but found no solution.
I also tried out sudo apt-get install ddd on another machine to go to the trouble out of the way, but then I only get authentication failure, which I also already asked without response on ask ubuntu.
Any help or hint is appreciated.
dl-debug.c:74 no such file or directory
This message means that you've tried to step into GLIBC (more precisely the dynamic loader) source, which you didn't install.
Solution: don't try to step into it, or install GLIBC source and make GDB find it (help directory).

How to load extra libraries for GDB?

I'm trying to debug a CUDA program, but when I'm launching gdb like so:
$ gdb -i=mi <program name>
$ r <program arguments>
I'm getting:
/home/wvxvw/Projects/cuda/exercise-1-udacity/cs344/HW2/hw:
error while loading shared libraries: libcudart.so.5.0:
cannot open shared object file: No such file or directory
Process gdb-inferior killed
(formatted for readability)
(I'm running gdb using M-xgdb) If that matters, then CUDA libraries are in the .bashrc
export PATH="/usr/local/cuda/bin:$PATH"
export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/usr/local/cuda/lib64"
error while loading shared libraries: libcudart.so.5.0
This error has nothing to do with GDB: your executable, when run from inside GDB, can't find the library it needs.
export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/usr/local/cuda/lib64"
GDB runs your program in a new $SHELL, so that should have worked. I wonder if there is some interaction with emacs.
In any case, this:
(gdb) set env LD_LIBRARY_PATH /usr/local/cuda/lib64
(gdb) run
should fix this problem.
Update:
as I've mentioned it before, ld path is set properly
No, it isn't. If it was, you wouldn't have the problem.
Now, I don't know why it isn't set properly. If you really want to find out, start by running GDB outside emacs (to exclude possible emacs interactions).
If the problem is still present, gdb show env, shell env, adding echo "Here" to your ~/.basrc, etc. should help you find where things are not working as you expect them.
I've had this problem as well. One way to look at it is that even if the LD_LIBRARY_PATH variable is correct when you enter show env into gdb, it may not be correct when you actually execute the program because gdb executes $SHELL -c <program> to run the program. Try this as a test, run $SHELL from the command line and then echo $LD_LIBRARY_PATH. Is it correct? If not, then you probably need to add it to your rc (.tcshrc in my case).
I had a similar problem when trying to run gdb on windows 7. I use MobaXterm to access a Linux toolbox. I installed gdb separately from http://www.gnu.org/software/gdb/ . I got it to work by making sure gdb could find the correct .dll files as mentioned by Employed Russian. If you have MobaXterm installed the .dll files should appear in your home directory in MobaXterm/slash/bin.
gdb however did not recognize the LD_LIBRARY_PATH variable. For me, it worked when I used the PATH variable instead:
(gdb) set env PATH C:\Users\Joshua\Documents\MobaXterm\slash\bin
(gdb) run
I would think using PATH instead of LD_LIBRARY_PATH might work for you provided you put the correct path to your library.
gdb is looking for a library, so why are you concerned with the include path? You may want to try to set the gdb option "solib-search-path" to point to the location of the libcudart.so.5.0 library.

Eclipse CDT 4.2 debug remote external program

I'd like to debug to debug a remote application with GDB.
My target system is a FreeBSD 8.3 box with gdbserver running. The application has been compiled successfully on that box. My Eclipse CDT 4.2 runs on Windows 7 with recent MinGW installed.
This is an external program I'd like to debug. It is neither written by me nor I do have it as a library. I do not intend to write my own program. In this case it is Subversion 1.8.0-dev which I want to debug.
I have created a simple C project, attached the source of Subversion. Created a remote debug config and attached the sources to the running thread in gdbserver.
Now, eclipse enters the main function of Subversion but when I set a breakpoint in another attached source file, Eclipse says: No source file named ra_loader.c or it simply says "No source available".
Then It simply exists the application.
What am I missing here?
Try the suggestion made on this thread
Quote :
1) run a debug session and open the gdb console inside Eclipse
('Console' tab -> 'Display Selected Console' button -> choose the one
ending with 'gdb')
2) use command 'pwd' in the console to print
gdb's current working dir
3) use command 'info line main' to get
the source file where gdb expect to find of my "int main(...)"
function
4) concatenate the result of step 2 with result of step
3 (which should be a relative path) to see if it matches the
correct source file I want
5) use the 'cd' command in gdb (to
change the current working dir) till I get the correct match in
step 4
Knowing the initial working directory (2) and the correct working directory (5) for gdb , I had 2 options: 1) Use gdb's 'cd'
command every time I launch a debug session (I could setup a
.gdbinit file in the gdb initial working directory to do this
automatically) or 2) Setup the 'Source' tab, in 'Debug
Configurations', to make Eclipse use paths that match with gdb's
initial working dir ('Project - Path Relative to Source Folders'
worked for me)

What needs to be done to get a distributable program from Eclipse?

I’ve produced a C++ program in Eclipse running on Redhat, which compiles and runs fine through Eclipse.
I thought that to run it separately to Eclipse you use the build artifact which is in the directory set via the project’s properties.
However this executable doesn’t run (I know it’s an executable as I’ve set it to be an executable via the project’s properties and it shows up as such via the ls command and the file explorer).
When attempting to run it using the executable’s name, I get the error:
bash: <filename>: command not found
When attempting to run it as a bash file:
<filename>: <filename>: cannot execute binary file
And when running it with "./" before the file name, nothing happens. Nothing new appears in the running processes and the terminal just goes to the next line as though I’d just pressed enter with no command.
Any help?
You've more or less figure out the first error yourself. when you just run <filename> , it is not in your PATH environment variable, so you get "command not found". You have to give a full or relative path when to the program in order to run it, even if you're in the same directory as the program - you run it with ./<filename>
When you do run your program, it appears to just exit as soon as you start it - we can't help much with that without knowing what the program does or see some code.
You can do some debugging, e.g. after the program just exits run echo $? to see if it exited with a particular exit value, or run your program using the strace tool to see what it does (or do it the usual way, insert printf debugging, or debug it with gdb)

Better variable exploring when debugging C++ code with Eclipse/CDT

Using Eclipse and CDT to debug C++ code the variable windows is cumbersome and not very informative for types defined in the standard template library or in boost (e.g. shared_ptr).
Just an example how this may look like for an std::vector:
bar {…}
std::_Vector_base<TSample<MyTraits>, std::allocator<TSample<MyTraits> > >
_M_impl {…}
std::allocator<TSample<MyTraits> > {…}
_M_start 0x00007ffff7fb5010
_M_finish 0x00007ffff7fd4410
_M_end_of_storage 0x00007ffff7fd5010
Even if this information about the internals of those types may be useful, in almost any cases I would expect a clearer presentation here, i.e. a list of values for the std::vector. Are there any tools, plugins or other modifications around which can do this?
EDIT
The following solutions does not work for linux. I am using ubuntu 14.04, eclipse, g++, gdb.
I cant find a package gdb-python and linux does not use mingw
You need a version of GDB capable of using python to pretty print structures. I know at least on windows using mingw that this is not provided in the default install.
Pretty Printers are python modules which tell gdb how to display a given structure. You can write your own, but there are already printers for STL available for download.
To Get Pretty Printers working on Windows (instructions should be similiar for other OS's):
Prerequisites
Make sure you have you have Python 2.7 installed and in the system path.
http://www.python.org/download/
Make sure MinGW-get is installed
http://sourceforge.net/projects/mingw/files/Installer/mingw-get-inst/
Make sure you have an SVN client are installed
Installation:
Open a command Shell and type:
mingw-get install gdb-python
When its finished cd to a local directory and install the printers by typing:
svn co svn://gcc.gnu.org/svn/gcc/trunk/libstdc++-v3/python
Open the .gdbinit (create it in a text editor if need be) and type the following replaceing "C:/directory" with the folder that you checked the printers into.
Python
import sys
sys.path.insert(0, 'C:/directory')
from libstdcxx.v6.printers import register_libstdcxx_printers
register_libstdcxx_printers (None)
end
Eclipse Setup
Go To Windows > Preferences > C/C++ > Debug > GDB
Where it Says GDB Debugger put the path to the python enabled GDB it will most likely be in the mingw /bin folder with a name like gdb-python27.exe
Where it says GDB Command File put the path to the .gdb init file you made earlier.
That's it, debug like normal, the stl structures should be much easier to read.
Well, gdb don't natively support STL containers. You can't say this is incorrect, since it will expose the inner workings of the STL objects, but most of the time it is not what we want, right?
If you're using gdb 7.0 you can take advantage of the pretty printers. This website http://sourceware.org/gdb/wiki/STLSupport has a pretty simple tutorial on how to set them. I copied below the part that interests you:
Check-out the latest Python libstdc++ printers to a place on your
machine. In a local directory, do:
svn co svn://gcc.gnu.org/svn/gcc/trunk/libstdc++-v3/python
Add the following to your ~/.gdbinit. The path needs to match
where the python module above was
checked-out. So if checked out to:
/home/maude/gdb_printers/, the path
would be as written in the example:
python
import sys
sys.path.insert(0, '/home/maude/gdb_printers/python')
from libstdcxx.v6.printers import register_libstdcxx_printers
register_libstdcxx_printers (None)
end
The path should be the only element
that needs to be adjusted in the
example above. Once loaded, STL
classes that the printers support
should printed in a more
human-readable format. To print the
classes in the old style, use the /r
(raw) switch in the print command
(i.e., print /r foo). This will print
the classes as if the Python
pretty-printers were not loaded.
Since you're using eclipse cdt, don't forget to point your debug configuration to your .gdbinit file. When creating a new Debug Configuration, go to the Debugger tab and put the path to the .gdbinit file in the "GDB command file" field.
I hope that helps!
In debug view in variables list expand vector:
"vector_name" -> std::_Vector_base<"datatype"> -> _M_impl
then right click on _M_start and select "Display as array...", type its length and then click OK. Now you can expand each item of your vector.
If you have gdb support for CDT (see, for example, GDB in Eclipse), you could try this: De-referencing STL containers
Long ago I also stumbled upon your same problem. It was a pain to check the STL containers. Then I found that link and added to my .gdbinit file some of those definitions. Life was easier after that.
NOTE: My gdb version is 7.1 and adding those definitions work fine. I don't know if in newer versions of gdb they are already included.
I would like to expand on the Windows 7 response because some key steps are left out:
This is for MinGW users with Eclipse CDT
0) If you don't have python GDB, open a shell/command and use MinGW-get.exe to 'install'
Python-enabled GDB e.g.
MinGw-get.exe install gdb-python
1a) Get Python 2.7.x from http://python.org/download/ and install
1b) Make sure PYTHONPATH and PYTHONHOME are set in your environment:
PYTHONPATH should be C:\Python27\Lib (or similar)
PYTHONHOME should be C:\Python27
1c) Add PYTHONHOME to your PATH
%PYTHONHOME%;...
2a) Open a text enter, enter the following statements. Notice the 3rd line is
pointing to where the python scripts are located. See notes below about this!
python
import sys
sys.path.insert(0, 'C:/MinGW/share/gcc-4.6.1/python')
from libstdcxx.v6.printers import register_libstdcxx_printers
register_libstdcxx_printers (None)
end
2b) Save as '.gdbinit' NOTE: Windows explorer will not let you name a file that starts with
with a period from explorer. Most text edits (including Notepad) will let you. GDB init
files are like 'scripts' of GDB commands that GBD will execute upon loading.
2c) The '.gdbinit' file needs to be in the working directory of GDB (most likely this is
your projects root directory but your IDE can tell you.
3) Open your Eclipse (or other IDE) Preferences dialog. Go to the C++ Debugger sub-menu.
4) Configure Eclipse to use C:\MinGW\bin\gdb-python27.exe as the debugger and your .gdbinit as the config file.
5a) Re-create all your debug launch configurations (delete the old one and create a new one from scratch).
--OR--
5b) Edit each debug configuration and point it to the new gdb-python.exe AND point it to the.
If you run into issues:
--Don't forget to change the location to the python directory in the above python code!
This directory is created by MinGW, so don't go looking to download the pretty printers, MinGW
did it for you in step zero. Just goto your MinGW install director, the share folder,
the GCC folder (has version number) and you will find python folder. This location is what
should be in python script loaded by GDB.
--Also, the .gdbinit is a PITA, make sure its named correctly and in the working folder of GDB
which isn't necessarily where gdb-python.exe is located! Look at your GDB output when loading GDB to see if a) 'python-enabled' appears during load and that the statements in the .gdbinit are appearing.
--Finally, I had alot of issues with the system variables. If python gives you 'ImportError' then most likely you have not set PYTHONPATH or PYTHONHOME.
--The directory with 'gdb-python27' (e.g. C:\MinGW\bin') should also be on your path and if it is, it makes setting up eclipse a bit nicer because you don't need to put in absolute paths. But still, sometimes the .gbdinit needs an absoulte path. if it works you'll see output from gbd (console->gdb traces) like this on startup of debugger:
835,059 4^done
835,059 (gdb)
835,059 5-enable-pretty-printing
835,069 5^done
....
835,129 12^done
835,129 (gdb)
835,129 13source C:\MinGW\bin\.gdbinit
835,139 &"source C:\\MinGW\\bin\\.gdbinit\n"
835,142 13^done
835,142 (gdb)
I know that JDT (Java environment in eclipse) provides custom "formatters" to be applied when displaying variable values in debug views. A quick look at google for the same in CDT brings this page:
http://wiki.eclipse.org/CDT/Better_Debugging_%28GSoC_project%29
I don't know if this has been yet integrated in the main CDT line, may be you can try to right click on a variable while debugging (in the last CDT) and see if there is a custom formater entry. If not available I recomend you to add a new tracker entry in CDT tracker to ask this enhancement.