generating branch coverage data for lcov

Question

i\'m trying to use lcov for code coverage metrics, but I cannot get branches coverage to work.

Here\'s how i\'m using it:

g++ -ggdb3 --coverage src/read.         


        

Answer 1

The latest version of LCOV disabled branch coverage by default.

You need to re-enable it by either:

• editing your ~/.lcovrc file (copied from /etc/lcovrc) to change lcov_branch_coverage setting to 1
• adding --rc lcov_branch_coverage=1 to your lcov command lines

Answer 2

Sorry, not so much an "idea" as a confirmation that you're doing everything correctly. Your exact commands worked on this simple code:

#include <iostream>
using namespace std;

bool foo(int i)
{
    if (i != 0) {
        return 12 / i;
    } else {
        return 0;
    }
}

int main(int argc, char** argv)
{
    cout << foo(argc) << endl;
    return 0;
}

The lcov coverage table has statistics for Lines, Functions, and Branches. Maybe double-check that you're actually looking at the correct output HTML?

Answer 3

based on this post, the difference may depend on the version of gcc you are using. Can you share which versions you are using. I am not getting branch coverage on:

 i686-apple-darwin11-llvm-gcc-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.11.00)

Answer 4

.lcovrc files is file of settings that need to place in path of lcov file. Frankly, I didn't research much on use of this file.

You need to add additional parameter as "--rc lcov_branch_coverage=1" to lcov for all calls. In your case add this parameter to all your three calls. If you miss one, it will drop branch coverage.

Also --branch-coverage is needed for genhtml.