Advanced GCC Usage

Abstract

GCC’s default behavior is usually what you want. Rather, GCC usually does The Right Thing and, at least in our experience, rarely violates the Principle of Least Surprise. As you have no doubt begun to appreciate by now, if you want GCC to do something, chances are pretty good that it has a command-line option that will make it do so. Nevertheless, what should you do if you dislike GCC’s default behavior, get tired of typing the same command-line option, and do not know enough to modify GCC’s code? Naturally, you customize GCC using environment variables or, as you will learn in the next section, specification (spec) strings.