Pretty Printers

GDB Pretty Printers for STL display nicely formatted variables in the hover pop-up and watch window, for all STL containers (vectors, maps, etc).

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Test with GDB

• Ensure GDB is python-enabled. For Linux (tested with recent Ubuntu), it is installed by default with GDB. For Windows, MinGW's default GDB is not python enabled. One option is to install MinGW-Builds over MinGW (consider backing up MinGW first). This updates GCC to 4.7.2 and includes a Python enabled GDB.

To test, launch GDB from console:

(gdb) python print sys.version

If python is enabled, the version will be printed (probably 2.7.1), otherwise, a message will indicate python scripting is not supported.

• Download the python printer (if necessary)

Windows users with MinGW should already have this file in /MinGW/share/gcc-4.7.2/python/libstdcxx/v6.

Linux users can download printers.py here. Store in /home/username/gdb_printers.

• Create a GDB Command File to enable the printer. Store in c:\mingw\bin\pp.gdb (windows) or /home/username/gdb_printers (linux). Below is a sample command file. Replace the path c:/MinGW/share... with your path to printers.py.

python
import sys
sys.path.insert(0, 'c:/MinGW/share/gcc-4.7.2/python/libstdcxx/v6')
from printers import register_libstdcxx_printers
register_libstdcxx_printers (None)
end

• Test

1. Set a breakpoint in a program and debug
2. Run the command file from GDB (can use Codeblocks->debugger tab->command, or in GDB from the console) (substitute your path if necessary)

(gdb) source c:\MinGW\bin\pp.gdb

3. Test the printer - example:

(gdb) print words2
$1 = std::vector of length 3, capacity 4 = {"one", "two", "three"}

Add to Codeblocks

Once the command file is correctly loading the python printer into GDB, there are two steps to activate in Codeblocks:

1. Set debugger initialization command (substitute your path as necessary):
   Codeblocks->Settings->Debugger->Default->Debugger initialization commands

source c:\MinGW\bin\pp.gdb

NOTE: A bug in the Linux version may prevent entering anything in the Debugger initialization commands field. Until this is fixed, a workaround is to edit ./home/username/.codeblocks/default.conf and change the INIT_COMMANDS value to something like:
<![CDATA[source /home/user/gdb_pprinters/pp.gdb]]>

2. Disable Codeblocks handling of watch values:

Codeblocks->Settings->Debugger->Default->Enable Watch Scripts = Unchecked

Other Info

Links:

GDB Python API

GDB Pretty Printing

To Do

The third column in the Codeblocks popup and watch window displays a long unformatted string. Codeblocks is calling the GDB whatis command. Can this command be Pretty-Printed?