Visual studio macros are great, probably I will write this in all posts that I write for macros :). Sometime back, I need to change a fairly big CF.NET application such a way that it will log a line on each function entry and on function exit. We were tracing for cause of intermittently occurring GWES.EXE error, and we were tracing it from multiple directions. The error code of GWES was 0xC0000005, which means someone was trying to access something, which was never allocated or is being accessed after releasing it. Application was multi-threaded, and hence it was difficult to understand which thread will do what at what time.

Moving back to original point, we wanted to log entry and exit of each functions. There can be more then one way to do that, but we have selected to change each functions. And to change each functions I have selected to use developer named “VS.NET macro”.

From macro it is possible to navigate through solution and projects. So macro first needs to find out all class types from a project, and then for each class, iterate through its member and find out functions that has body. If function has body, inject the code that logs line on function entry and exit.

It was easy to find function entry, but there can be many way function ends, like exception is being thrown, or based of some condition it may execute “return”, or body of the function is ended and hence return. To accommodate such cases, we decide to use “using statement” of C#.

All right, enough of the background, have look at Macro code here