2016-05-25 Wednesday - Fixing my GDB (and Eclipse CDT Debugging capability)

I previously had my Windows 10 development machine configured to successfully develop and debug C++ programs from within Mars Eclipse - leveraging CDT and Cygwin.

I recently made some changes to my system configuration - and broke my Cygwin GDB debugging functionality.

After spending a few hours exploring the problem, I thought sharing this post might help someone else minimize their cycle time if they have a similar problem...

The first clue was in a Windows Command Prompt, I got the following error when trying to launch GDB:

"ImportError: No module named site"

Also, in Eclipse, when attempting to launch the debugger for a C++ program, I encountered this error message:

 "Could not determine DGB version using command gdb --version"

I  read several forum postings - and these were the relevant takeaways:

• http://stackoverflow.com/questions/5599872/python-windows-importerror-no-module-named-site
• https://docs.python.org/2/using/windows.html
• https://docs.python.org/3/using/windows.html
• "The PYTHONPATH variable is used by all versions of Python 2 and Python 3, so you should not permanently configure this variable unless it only includes code that is compatible with all of your installed Python versions."
• "he Python launcher for Windows is a utility which aids in locating and executing of different Python versions"
• "System-wide installations of Python 3.3 and later will put the launcher on your PATH. The launcher is compatible with all available versions of Python," 

Now, in my environment, I had setup Python 2.7.11 and Python 3.5.1 - and since GDB relies on Python 2.7 - I thought, "ah, perhaps one of my library installs / updates has resulted in a broken dependency situation". So, I uninstalled and re-installed them both. 

No joy.

I then uninstalled and re-installed Cygwin.

No joy.

Then I tried alternating where PYTHONHOME and PYTHONPATH pointed...to 2.7 vs 3.5

No joy.

Finally, I removed the System Variables for PYTHONHOME and PYTHONPATH.

Success. 

When in the Cygwin bash shell (or Windows Command Prompt window) - the Windows System Variables for PYTHONHOME and PYTHONPATH were conflicting with the Python 2.7 version that is bundled with Cygwin - and a dependency for GDB.

So I then just added the dir for Python 3.5 directly to the PATH environment variable. 

Problem solved.