Bullseye Code Coverage May 2026
// The tool tracks both true and false evaluations.
covmetric -p coverage.cov | grep "Decision Coverage" | awk 'if ($3 < 80) exit 1' The landscape has shifted. Here's when to choose Bullseye vs. newer tools:
This article provides a deep dive into the architecture, methodology, unique features, and strategic implementation of Bullseye Code Coverage. Bullseye is not just a line counter; it is a decision coverage tool. Its core philosophy is that simply knowing which lines of code executed (line coverage) is insufficient for identifying hidden logical flaws. bullseye code coverage
set(CMAKE_C_COMPILER "covc" CACHE STRING "") set(CMAKE_CXX_COMPILER "covc" CACHE STRING "") set(CMAKE_CXX_COMPILER_LAUNCHER "" CACHE STRING "") set(CMAKE_C_COMPILER_ARG1 "--compiler" CACHE STRING "") set(CMAKE_CXX_COMPILER_ARG1 "--compiler" CACHE STRING "") export PATH=/usr/local/bullseye/bin:$PATH covselect --add --on # Turn on coverage measurement cmake -DCMAKE_TOOLCHAIN_FILE=bullseye-toolchain.cmake .. covbuild cmake --build . --parallel Step 3: Run Tests & Capture Data cov01 -1 # Reset counters to zero ./bin/my_unit_tests covrun ./bin/integration_tests Step 4: Merge & Report covmerge -a *.cov # Merge all .cov files into one covhtml --title "Sprint 23 Coverage" -o coverage_html coverage.cov Step 5: Set a Quality Gate In your CI script, fail the build if decision coverage drops below 80%:
The instrumented source is then compiled and linked with Bullseye’s runtime library. You run your test suite normally (unit tests, integration tests, fuzzing). As the binary executes, the probes increment counters in shared memory or a .cov data file. Bullseye is remarkably low-overhead—typically 10-30% slowdown, making it viable for large test suites. Phase 3: Merging & Reporting ( covselect , covbr , covhtml ) This is where Bullseye shines. You can run tests across 1000 different processes, on different machines, at different times, and then merge all the .cov files into a single aggregate report. The command covmerge intelligently sums counters without double-counting. 3. Deep Dive: Decision Coverage (The "True" Bullseye Metric) Many teams erroneously believe 100% line coverage equals "tested." Consider this C++ function: // The tool tracks both true and false evaluations
Introduction: The Evolution of Code Coverage Tools In the landscape of software quality assurance, code coverage metrics serve as the bedrock for understanding how thoroughly your tests exercise your application. While open-source tools like gcov (GCC) and lcov are widely known, the commercial sector has long relied on a powerful, precision-focused solution: Bullseye Coverage .
// After Bullseye instrumentation (conceptual) probe_1 = 0; // Counter for the decision if (temperature > 100 && pressure < 50) probe_1++; // Counts entry of the true branch activate_alarm(); newer tools: This article provides a deep dive
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