Thread: How can I call the method in OPTIMIZER_DEBUG?

I have built PostgreSQL 9.3.1 from source code. But I want to use the print_path() method in src/backend/optimizer/path/allpaths.c which is at the bottom of allpaths.c in "DEBUG SUPPORT" section. My question is: a) How to run the postgresql server, or how to compile the source code so that I can call the print_path() method; b) Where can I find the output of printf statements in print_path()? In Log file? Because I assume it wouldn't output to the terminal.