gcov

Generate a coverage report named file.cpp.gcov

$ gcov [path/to/file.cpp]

$ gcov -a [path/to/file.cpp]

$ gcov -b [path/to/file.cpp]

$ gcov -c [path/to/file.cpp]

$ gcov -n [path/to/file.cpp]

$ gcov -f [path/to/file.cpp]

gcov [options] source-files

gcov is a test coverage program used with GCC to analyze which parts of a program have been executed during testing. It helps identify untested code paths, improving test suite completeness.
To use gcov, compile your program with -fprofile-arcs -ftest-coverage (or --coverage). After running the program, gcov reads the generated .gcno and .gcda files to produce annotated source listings showing execution counts for each line.
Output files (*.gcov) contain the original source code annotated with execution counts. Lines marked ##### were never executed. Branch information helps identify untested conditional paths.

-a, --all-blocks

Write individual execution counts for every basic block

Write branch frequencies to output file as percentages

Write branch frequencies as counts rather than percentages

Output summaries for each function in addition to file summary

Do not create gcov output file

Use long file names for output files

Preserve complete path information in output file names

Search for object files in DIR

Remove source path prefix for shorter output names

Requires programs to be compiled with special GCC flags. Only works with GCC-compiled code. Running the program multiple times accumulates coverage data unless .gcda files are deleted between runs. Inline functions may show misleading counts.

gcov has been part of the GNU Compiler Collection (GCC) since the early 1990s. It evolved alongside GCC's profiling capabilities and remains a fundamental tool for C/C++ code coverage analysis in the open-source ecosystem.

gcc(1), lcov(1), gprof(1)