title: When to use the -g flag to GCC
body: <p>I'm trying to force ValGrind to tell me what's wrong with my program. Every shred of documentation on the face of the Internet says that you must supply the <code>-g</code> option to GCC, but not one single document says whether you need this flag at <em>compile-time</em> or <em>link-time</em> (or both). So which is it??</p>