gcov vs grcov

gcov is a free test coverage tool used with GCC to show how program code runs during testing. It reports which source lines execute and how often, producing per-line counts in `.gcov` files. Reports can include line, function, branch, condition, prime-path, and basic-block coverage. Options can report branch frequencies, show whether conditions independently affect a Boolean expression’s result, or filter reports to functions matching regular expressions. Output is available as `.gcov` text or gzip-compressed JSON; JSON generation does not require source code. The GCC documentation also describes using gcov with gprof to assess computing time, while warning that optimization can combine source lines and reduce hotspot detail. Before coverage reporting, programs must be compiled with GCC’s `--coverage` option. gcov works only with GCC-compiled code and is not compatible with other profiling or test coverage mechanisms. It runs on Linux, macOS, and Windows, supports the listed languages from C and C++ to Ada, D, and Go, and is self-hosted.

grcov has no write-up on Specifiction yet; its figures are above.