Configuration for debugging deal.II projects via GDB

deal.II comes with a simple set of pretty-printers that provide descriptions to GDB (the GNU debugger) on how to usefully print deal.II objects. For example, without pretty-printing, GDB prints points as

(gdb) print point
$1 = {<dealii::Tensor<1, 2, double>> = {static dimension = <optimized out>,
static rank = <optimized out>, static n_independent_components = <optimized out>, values = {{
static dimension = <optimized out>, static rank = <optimized out>,
static n_independent_components = <optimized out>, value = 0}, {
static dimension = <optimized out>, static rank = <optimized out>,
static n_independent_components = <optimized out>, value = 0}}}, <No data fields>}

(gdb) print point
$1 = {0, 0}

Setting up GDB for just deal.II

If you only plan on using GDB with deal.II then it suffices to rename the provided GDB pretty-printing file and place it in your home directory. This can be done with the following shell commands (where dealii_source_directory is the root directory containing all deal.II source files):

cd dealii_source_directory
cp contrib/utilities/dotgdbinit.py ~/.gdbinit

Setting up GDB for deal.II and other sets of printers

Configuring GDB to use multiple sets of pretty-printers (i.e., sets of pretty-printers from deal.II as well as other projects) takes a little more work. The recommended procedure is

1. Decide on a directory where you will place all of your pretty-printing files. A good choice would be creating a new folder .gdbscripts in your home directory, and this is the choice assumed for the rest of this demonstration.
2. Move the Python source code parts (so everything after, and not including, the line containing just the word python near the beginning up to (and also not including) the line containing just the word end) of the file contrib/utilities/dotgdbinit.py into the directory from the first step. Rename this file to deal.py so that we can import it into the principal GDB configuration file in the next step.
3. Add the following to your .gdbinit file, which also resides in your home directory:

   set print pretty 1
   
   python
   
   import os
   import sys
   sys.path.append(os.path.expanduser("~/.gdbscripts/"))
   import deal
   
   end

   The statements between python and end are executed as python code by GDB. The line

   import deal

   executes the code necessary to enable the deal.II pretty-printers (it loads the file created in the last step).