Coredump

From Fluxbox-wiki

Compiling with the Appropriate Options

Enabling debug output when compiling fluxbox will print a lot of messages to your stderr about what fluxbox is doing while it runs. This is not required to get a core dump, but you and/or the developers may find it useful if you provide it.

If you have used a package to install fluxbox with instead of the source you will need to use the source, follow this guide.

Now what we need to do is move to the directory where our fluxbox source is. I use SVN fluxbox so what I will do is:

 cd ~/fluxbox

Now that I am in my directory where the fluxbox src is I will issue the following command:

 CXXFLAGS="-g" LDFLAGS="-g" ./configure  --enable-debug --enable-imlib2 --enable-xinerama

This will enable imlib2 for png support, debug symbols, and xinerama for my dual head support. The first part of the command enables debug information for gdb which is a debug tool many developers use. Once this command has finished running issue the following command to build fluxbox:

 make clean && make

Once this has finished you will need to gain super user privilege (aka root) to finish the install. I will be using sudo for this, you could use su - if you want:

 sudo make install

Make sure you do not run `strip' on the created executable file, as this will remove all useful information from the core dump. Running the following command should show you the size of the fluxbox executable installed in your system. It should be about 10MB instead of about 1MB.

 ls -l `command -v fluxbox`

Wrapping Up

All we need to do now is run this command before we start fluxbox:

 ulimit -c unlimited

This command allows your shell environment to create the core dump and will allow it to be as large as it needs to be.

Next just start fluxbox

 startx /path/to/fluxbox

Now all you need to do is get your fluxbox to crash. Your core file will be in your $HOME directory and a file named "core" depending on your system.

It may be more convenient to run fluxbox on a second x server. You can do this by running the following command

 startx /path/to/fluxbox -- :1

When your fluxbox crashes, this will return you to your desktop instead of a tty.

Getting a Backtrace

If you're reading this, you've almost certainly been told to get a backtrace from a crash. Once you have a core file, you're almost ready to get the backtrace. If you don't have it, you will need to install `gdb'. Then, run the following command:

 gdb /path/to/fluxbox /path/to/core

You will see a lot of output, followed by a prompt that looks like this:

 (gdb)

Type `bt', press enter, and you will be presented with the backtrace. You can exit the program by typing `q', followed by enter.