Difference between revisions of "Pretty Printers"

From Code::Blocks
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*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 [http://sourceforge.net/projects/mingwbuilds/ MinGW-Builds] over MinGW (consider backing up MinGW first). This updates GCC to 4.7.2 and includes a Python enabled 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 [http://sourceforge.net/projects/mingwbuilds/ MinGW-Builds] over MinGW (consider backing up MinGW first). This updates GCC to 4.7.2 and includes a Python enabled GDB.
 
<ol>
 
<ol>
To test:<br/>
+
To test, launch GDB from console:
Launch GDB from console:
 
 
<span style="font-size: 10pt"><pre>
 
<span style="font-size: 10pt"><pre>
 
(gdb) python print sys.version
 
(gdb) python print sys.version
</pre></span></ol>
+
</pre></span>
 +
If python is enabled, the version will be printed (probably 2.7.1), otherwise, a message will indicate python scripting is not supported.
 +
</ol>
 
*Create a GDB [http://sourceware.org/gdb/onlinedocs/gdb/Command-Files.html Command File] to enable the printer. Store in c:\mingw\bin\pp.gdb (or wherever you want). Below is a sample command file. Replace the path c:/MinGW/share... 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 loaded into GDB's python, which is the purpose of the command file
 
*Create a GDB [http://sourceware.org/gdb/onlinedocs/gdb/Command-Files.html Command File] to enable the printer. Store in c:\mingw\bin\pp.gdb (or wherever you want). Below is a sample command file. Replace the path c:/MinGW/share... 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 loaded into GDB's python, which is the purpose of the command file
 
<blockquote><span style="font-size: 10pt"><pre>
 
<blockquote><span style="font-size: 10pt"><pre>

Revision as of 22:03, 26 October 2012

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


Popup example

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.

  • Create a GDB Command File to enable the printer. Store in c:\mingw\bin\pp.gdb (or wherever you want). Below is a sample command file. Replace the path c:/MinGW/share... 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 loaded into GDB's python, which is the purpose of the command file
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
  1. 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
  1. 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?