How to make an old C codebase with many globals reentrant

Question

I'm working with a large, old C codebase (an interpreter) that uses global variables a great deal, with the result that I cannot have two instances of it at once. Is there a straightforward (ideally automated) approach to convert this code to something reentrant? i.e. some refactor tool that would make all globals part of a struct and prepend the pointer to all variables?

Could I convert to C++ and wrap the entire thing in a class definition?

Answer 1

I would recommend to convert your project into C++11 project and change all your static vars into threadlocal.

This can be up to several days of work depending on the size of your project. In certain cases this will work.