Pretty Printers

From Code::Blocks
Revision as of 17:14, 25 October 2012 by GravityWe11 (talk | contribs)

GDB Pretty Printers for STL output nicely formatted variables, even for vectors and maps. This works in GDB, and if enabled, in the hover pop-up and watch window in Code::Blocks.


Pprint1.png
UNDER CONSTRUCTION

Step 1 - Test with GDB

  • Install a python-enabled GDB. For Windows, you can install MinGW-Builds over MinGW (consider backing up MinGW first). This updates GCC to 4.7.2 and includes a Python enabled GDB.
  • Create a GDB Command File to enable the printer. Store in c:\mingw\bin\pp.gdb (or wherever you want). Here is a sample command file. Replace the path with your path to printers.py. NOTE: A Python STL printer.py is included with MinGW and MinGW-Builds, so there is no need to download one. It only needs to be turned on, which is the purpose of the command file
python
import os, sys
lib_path = os.path.abspath('c:/MinGW/share/gcc-4.7.0/python/libstdcxx/v6')
sys.path.append(lib_path)
#print 'path is [%s]' % ', '.join(map(str, sys.path))
from printers import register_libstdcxx_printers
register_libstdcxx_printers (None)
end
  • Test
  1. Set a breakpoint in a program and debug
  2. Run GDB command file (can use Codeblocks debugger tab command, or GDB from console) (substitute your path if necessary)
    (gdb) source c:\MinGW\bin\pp.gdb
  1. Test the printer - example:
    (gdb) print words2
    $1 = std::vector of length 3, capacity 4 = {"one", "two", "three"}
    

Step 2 - Add to Codeblocks

Once the printer works in GDB, there are two steps to activate in Codeblocks:

  1. Set debugger initialization command
    settings->debugger->default->debugger initialization commands
    source $(TARGET_COMPILER_DIR)bin\pp.gdb
  1. Comment out the Codeblocks gdb handler
    Edit pathto-Codeblocks\share\CodeBlocks\scripts\gdb_types.script
    Add comments as follows:
    /* STL String
    driver.RegisterType(
        _T("STL String"),
        _T("[^[:alnum:]_]*string[^[:alnum:]_]*"),
        _T("Evaluate_StlString"),
        _T("Parse_StlString")
    );*/

    /* STL Vector
    driver.RegisterType(
        _T("STL Vector"),
        _T("[^[:alnum:]_]*vector<.*"),
        _T("Evaluate_StlVector"),
        _T("Parse_StlVector")
    ); */

[u]Other Info[/u] Links: http://sourceware.org/gdb/onlinedocs/gdb/Python-API.html http://sourceware.org/gdb/onlinedocs/gdb/Pretty-Printing.html

[u]To Do[/u] 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?