BSD/Plan 9 style is extremely useful because it allows grepping for functions. More specifically, it allows the creation of acme(1) addresses of the form /some/file.c:/^foo where foo is a function. In acme you can just B3-click on that string and it will open the file at the correct function...
It is also a pretty common style in the open source world.
It is also a pretty common style in the open source world.