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                        <h1 id="gcov1"><a class="header" href="#gcov1">gcov(1)</a></h1>
<p>Generate code coverage reports in text format.</p>
<p>Compile the source files of interest and link the final binary with the
following flags:</p>
<ul>
<li><code>-fprofile-arcs</code> instruments the generated code such that it writes a <code>.gcda</code>
file when being executed with details about which branches are taken</li>
<li><code>-ftest-coverage</code> writes a <code>.gcno</code> notes file which is used by <code>gcov</code> during
generation of the coverage report</li>
</ul>
<p>Depending on the build environment one may also set <code>-fprofile-abs-path</code> to
generate absolute path names into the <code>.gcno</code> note files, this can ease setups
where compilations are done in different directories to the source directory.</p>
<blockquote>
<p><code>gcc</code> / <code>clang</code> also support an alias flag <code>--coverage</code> which during
compilation time is equivalent to <code>-fprofile-arcs -ftest-coverage</code> and during
link time <code>-lgcov</code>.</p>
</blockquote>
<p>After running the instrumented binary, the human readable report can then be
generated for a single file for example such as</p>
<pre><code class="language-shell">gcov &lt;SRC FILE | OBJ FILE&gt;
</code></pre>
<h2 id="example"><a class="header" href="#example">Example</a></h2>
<pre><code class="language-cpp">#include &lt;cstdio&gt;

void tell_me(int desc) {
  if (desc &amp; 1) {
    std::puts("this");
  } else {
    std::puts("that");
  }
}

int main(int argc, char *argv[]) {
  tell_me(argc);
  tell_me(argc);
  return 0;
}
</code></pre>
<p>The <code>gcov</code> coverage report can be generated as follows for <code>gcc</code> or <code>clang</code>.</p>
<pre><code class="language-make">CXXFLAGS = -fprofile-arcs -ftest-coverage
# or the alias
#CXXFLAGS = --coverage

cov-gcc: clean
	g++ $(CXXFLAGS) -c -o cov.o cov.cc
	g++ $(CXXFLAGS) -o $@ cov.o
	./$@
	gcov --demangled-names cov.cc
	cat cov.cc.gcov
.PHONY: cov-gcc

cov-clang: clean
	clang++ $(CXXFLAGS) -c -o cov.o cov.cc
	clang++ $(CXXFLAGS) -o $@ cov.o
	./$@
	llvm-cov gcov --demangled-names cov.cc
	cat cov.cc.gcov
.PHONY: cov-clang

clean:
	$(RM) *.gcov *.gcno *.gcda *.o cov-*
</code></pre>
<p>The will generate a report similar to the following.</p>
<pre><code class="language-text">cat cov.cc.gcov
        -:    0:Source:cov.cc
        -:    0:Graph:cov.gcno
        -:    0:Data:cov.gcda
        -:    0:Runs:1
        -:    1:// Copyright (C) 2023 johannst
        -:    2:
        -:    3:#include &lt;cstdio&gt;
        -:    4:
        2:    5:void tell_me(int desc) {
        2:    6:  if (desc &amp; 1) {
        2:    7:    std::puts("this");
        -:    8:  } else {
    #####:    9:    std::puts("that");
        -:   10:  }
        2:   11:}
        -:   12:
        1:   13:int main(int argc, char *argv[]) {
        1:   14:  tell_me(argc);
        1:   15:  tell_me(argc);
        1:   16:  return 0;
        -:   17:}
</code></pre>

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                        <h1 id="gcov1"><a class="header" href="#gcov1">gcov(1)</a></h1>
<p>Generate code coverage reports in text format.</p>
<p>Compile the source files of interest and link the final binary with the
following flags:</p>
<ul>
<li><code>-fprofile-arcs</code> instruments the generated code such that it writes a <code>.gcda</code>
file when being executed with details about which branches are taken</li>
<li><code>-ftest-coverage</code> writes a <code>.gcno</code> notes file which is used by <code>gcov</code> during
generation of the coverage report</li>
</ul>
<p>Depending on the build environment one may also set <code>-fprofile-abs-path</code> to
generate absolute path names into the <code>.gcno</code> note files, this can ease setups
where compilations are done in different directories to the source directory.</p>
<blockquote>
<p><code>gcc</code> / <code>clang</code> also support an alias flag <code>--coverage</code> which during
compilation time is equivalent to <code>-fprofile-arcs -ftest-coverage</code> and during
link time <code>-lgcov</code>.</p>
</blockquote>
<p>After running the instrumented binary, the human readable report can then be
generated for a single file for example such as</p>
<pre><code class="language-shell">gcov &lt;SRC FILE | OBJ FILE&gt;
</code></pre>
<h2 id="example"><a class="header" href="#example">Example</a></h2>
<pre><code class="language-cpp">#include &lt;cstdio&gt;

void tell_me(int desc) {
  if (desc &amp; 1) {
    std::puts("this");
  } else {
    std::puts("that");
  }
}

int main(int argc, char *argv[]) {
  tell_me(argc);
  tell_me(argc);
  return 0;
}
</code></pre>
<p>The <code>gcov</code> coverage report can be generated as follows for <code>gcc</code> or <code>clang</code>.</p>
<pre><code class="language-make">CXXFLAGS = -fprofile-arcs -ftest-coverage
# or the alias
#CXXFLAGS = --coverage

cov-gcc: clean
	g++ $(CXXFLAGS) -c -o cov.o cov.cc
	g++ $(CXXFLAGS) -o $@ cov.o
	./$@
	gcov --demangled-names cov.cc
	cat cov.cc.gcov
.PHONY: cov-gcc

cov-clang: clean
	clang++ $(CXXFLAGS) -c -o cov.o cov.cc
	clang++ $(CXXFLAGS) -o $@ cov.o
	./$@
	llvm-cov gcov --demangled-names cov.cc
	cat cov.cc.gcov
.PHONY: cov-clang

clean:
	$(RM) *.gcov *.gcno *.gcda *.o cov-*
</code></pre>
<p>The will generate a report similar to the following.</p>
<pre><code class="language-text">cat cov.cc.gcov
        -:    0:Source:cov.cc
        -:    0:Graph:cov.gcno
        -:    0:Data:cov.gcda
        -:    0:Runs:1
        -:    1:// Copyright (C) 2023 johannst
        -:    2:
        -:    3:#include &lt;cstdio&gt;
        -:    4:
        2:    5:void tell_me(int desc) {
        2:    6:  if (desc &amp; 1) {
        2:    7:    std::puts("this");
        -:    8:  } else {
    #####:    9:    std::puts("that");
        -:   10:  }
        2:   11:}
        -:   12:
        1:   13:int main(int argc, char *argv[]) {
        1:   14:  tell_me(argc);
        1:   15:  tell_me(argc);
        1:   16:  return 0;
        -:   17:}
</code></pre>

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