title: Getting useful GCov results for header-only libraries
body: <p>For my header-only C++ library (lots of templates etc) I use GCov to check test coverage. However, it reports 100% coverage for all headers because the unused functions aren't generated by the compiler in the first place. Manually spotting uncovered functions is easy but defeats the purpose of continuous integration…</p>
  
  <p>How does one solve this automatically? Should I just use "lines hit / LOC" as my coverage metric and just never reach 100% again?</p>