gcov vs Microsoft Code Coverage

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.

Microsoft Code Coverage measures how much of a project’s code is exercised by coded tests, such as unit tests. Its documented workflows cover.NET test projects with `dotnet test` and other.NET applications with the `dotnet-coverage` tool. It analyzes managed CLR and unmanaged native code using static or dynamic instrumentation; native coverage is disabled by default in the MTP extension. With Microsoft.Testing.Platform.MSBuild, extensions are auto-registered with MSTest, NUnit, and xUnit runners. The MTP extension can produce coverage, XML, and Cobertura reports, with settings for output, inclusion and exclusion rules, and instrumentation. It runs on Windows, macOS, and multiple Linux distributions, though instrumentation support varies by OS, version, and architecture. Other operating systems are supported on a best-effort basis, and some combinations allow static instrumentation only. Dynamic instrumentation on macOS and Linux requires libxml2, and missing dependencies may leave a report empty. MTP also excludes test assemblies by default unless configured otherwise. The plan is free.