I realize there's no definitely "right" answer to this question, but when people talk about lines of code, what do they mean? In C++ for example, do you count blank lines? Comments? Lines with just an open or close brace?
I know some people use lines of code as a productivity measure, and I'm wondering if there is a standard convention here. Also, I think there's a way to get various compilers to count lines of code - is there a standard convention there?
No, there is no standard convention, and every tool that counts them will be slightly different.
This may make you ask, "Why then would I ever use LOC as a productivity measure?" and the answer is, because it doesn't really matter how you count a line of code, as long as you count them consistently you can get some idea of the general size of a project in relation to others.