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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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                <ol class="chapter"><li class="chapter-item expanded affix "><a href="../intro.html">Introduction</a></li><li class="chapter-item expanded "><a href="../tools/index.html"><strong aria-hidden="true">1.</strong> Tools</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../tools/zsh.html"><strong aria-hidden="true">1.1.</strong> zsh</a></li><li class="chapter-item expanded "><a href="../tools/bash.html"><strong aria-hidden="true">1.2.</strong> bash</a></li><li class="chapter-item expanded "><a href="../tools/fish.html"><strong aria-hidden="true">1.3.</strong> fish</a></li><li class="chapter-item expanded "><a href="../tools/tmux.html"><strong aria-hidden="true">1.4.</strong> tmux</a></li><li class="chapter-item expanded "><a href="../tools/git.html"><strong aria-hidden="true">1.5.</strong> git</a></li><li class="chapter-item expanded "><a href="../tools/awk.html"><strong aria-hidden="true">1.6.</strong> awk</a></li><li class="chapter-item expanded 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href="../tools/ffmpeg.html"><strong aria-hidden="true">1.15.</strong> ffmpeg</a></li><li class="chapter-item expanded "><a href="../tools/column.html"><strong aria-hidden="true">1.16.</strong> column</a></li><li class="chapter-item expanded "><a href="../tools/sort.html"><strong aria-hidden="true">1.17.</strong> sort</a></li><li class="chapter-item expanded "><a href="../tools/sed.html"><strong aria-hidden="true">1.18.</strong> sed</a></li><li class="chapter-item expanded "><a href="../tools/gnuplot.html"><strong aria-hidden="true">1.19.</strong> gnuplot</a></li></ol></li><li class="chapter-item expanded "><a href="../monitor/index.html"><strong aria-hidden="true">2.</strong> Resource analysis & monitor</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../monitor/lsof.html"><strong aria-hidden="true">2.1.</strong> lsof</a></li><li class="chapter-item expanded "><a href="../monitor/ss.html"><strong aria-hidden="true">2.2.</strong> ss</a></li><li class="chapter-item expanded "><a href="../monitor/pidstat.html"><strong aria-hidden="true">2.3.</strong> pidstat</a></li><li class="chapter-item expanded "><a href="../monitor/pgrep.html"><strong aria-hidden="true">2.4.</strong> pgrep</a></li><li class="chapter-item expanded "><a href="../monitor/ps.html"><strong aria-hidden="true">2.5.</strong> ps</a></li><li class="chapter-item expanded "><a href="../monitor/pmap.html"><strong aria-hidden="true">2.6.</strong> pmap</a></li><li class="chapter-item expanded "><a href="../monitor/pstack.html"><strong aria-hidden="true">2.7.</strong> pstack</a></li></ol></li><li class="chapter-item expanded "><a href="../trace_profile/index.html"><strong aria-hidden="true">3.</strong> Trace and Profile</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../trace_profile/time.html"><strong aria-hidden="true">3.1.</strong> time</a></li><li class="chapter-item expanded "><a href="../trace_profile/strace.html"><strong aria-hidden="true">3.2.</strong> strace</a></li><li class="chapter-item expanded "><a href="../trace_profile/ltrace.html"><strong aria-hidden="true">3.3.</strong> ltrace</a></li><li class="chapter-item expanded "><a href="../trace_profile/perf.html"><strong aria-hidden="true">3.4.</strong> perf</a></li><li class="chapter-item expanded "><a href="../trace_profile/oprofile.html"><strong aria-hidden="true">3.5.</strong> OProfile</a></li><li class="chapter-item expanded "><a href="../trace_profile/callgrind.html"><strong aria-hidden="true">3.6.</strong> callgrind</a></li></ol></li><li class="chapter-item expanded "><a href="../binary/index.html"><strong aria-hidden="true">4.</strong> Binary</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../binary/od.html"><strong aria-hidden="true">4.1.</strong> od</a></li><li class="chapter-item expanded "><a href="../binary/xxd.html"><strong aria-hidden="true">4.2.</strong> xxd</a></li><li class="chapter-item expanded "><a href="../binary/readelf.html"><strong aria-hidden="true">4.3.</strong> readelf</a></li><li class="chapter-item expanded "><a href="../binary/objdump.html"><strong aria-hidden="true">4.4.</strong> objdump</a></li><li class="chapter-item expanded "><a href="../binary/nm.html"><strong aria-hidden="true">4.5.</strong> nm</a></li></ol></li><li class="chapter-item expanded "><a href="../development/index.html"><strong aria-hidden="true">5.</strong> Development</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../development/c++filt.html"><strong aria-hidden="true">5.1.</strong> c++filt</a></li><li class="chapter-item expanded "><a href="../development/c++.html"><strong aria-hidden="true">5.2.</strong> c++</a></li><li class="chapter-item expanded "><a href="../development/glibc.html"><strong aria-hidden="true">5.3.</strong> glibc</a></li><li class="chapter-item expanded "><a href="../development/gcc.html"><strong aria-hidden="true">5.4.</strong> gcc</a></li><li class="chapter-item expanded "><a href="../development/cmake.html"><strong aria-hidden="true">5.5.</strong> cmake</a></li><li class="chapter-item expanded "><a href="../development/make.html"><strong aria-hidden="true">5.6.</strong> make</a></li><li class="chapter-item expanded "><a href="../development/ld.so.html"><strong aria-hidden="true">5.7.</strong> ld.so</a></li><li class="chapter-item expanded "><a href="../development/symbolver.html"><strong aria-hidden="true">5.8.</strong> symbol versioning</a></li><li class="chapter-item expanded "><a href="../development/python.html"><strong aria-hidden="true">5.9.</strong> python</a></li><li class="chapter-item expanded "><a href="../development/gcov.html" class="active"><strong aria-hidden="true">5.10.</strong> gcov</a></li><li class="chapter-item expanded "><a href="../development/pgo.html"><strong aria-hidden="true">5.11.</strong> pgo</a></li></ol></li><li class="chapter-item expanded "><a href="../linux/index.html"><strong aria-hidden="true">6.</strong> Linux</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../linux/systemd.html"><strong aria-hidden="true">6.1.</strong> systemd</a></li><li class="chapter-item expanded "><a href="../linux/coredump.html"><strong aria-hidden="true">6.2.</strong> coredump</a></li><li class="chapter-item expanded "><a href="../linux/ptrace_scope.html"><strong aria-hidden="true">6.3.</strong> ptrace_scope</a></li><li class="chapter-item expanded "><a href="../linux/cryptsetup.html"><strong aria-hidden="true">6.4.</strong> cryptsetup</a></li><li class="chapter-item expanded "><a href="../linux/swap.html"><strong aria-hidden="true">6.5.</strong> swap</a></li><li class="chapter-item expanded "><a href="../linux/input.html"><strong aria-hidden="true">6.6.</strong> input</a></li><li class="chapter-item expanded "><a href="../linux/acl.html"><strong aria-hidden="true">6.7.</strong> acl</a></li><li class="chapter-item expanded "><a href="../linux/zfs.html"><strong aria-hidden="true">6.8.</strong> zfs</a></li></ol></li><li class="chapter-item expanded "><a href="../network/index.html"><strong aria-hidden="true">7.</strong> Network</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../network/tcpdump.html"><strong aria-hidden="true">7.1.</strong> tcpdump</a></li><li class="chapter-item expanded "><a href="../network/tshark.html"><strong aria-hidden="true">7.2.</strong> tshark</a></li><li class="chapter-item expanded "><a href="../network/firewall-cmd.html"><strong aria-hidden="true">7.3.</strong> firewall-cmd</a></li><li class="chapter-item expanded "><a href="../network/nftables.html"><strong aria-hidden="true">7.4.</strong> nftables</a></li></ol></li><li class="chapter-item expanded "><a href="../web/index.html"><strong aria-hidden="true">8.</strong> Web</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../web/html.html"><strong aria-hidden="true">8.1.</strong> html</a></li><li class="chapter-item expanded "><a href="../web/css.html"><strong aria-hidden="true">8.2.</strong> css</a></li><li class="chapter-item expanded "><a href="../web/chartjs.html"><strong aria-hidden="true">8.3.</strong> chartjs</a></li></ol></li><li class="chapter-item expanded "><a href="../arch/index.html"><strong aria-hidden="true">9.</strong> Arch</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../arch/x86_64.html"><strong aria-hidden="true">9.1.</strong> x86_64</a></li><li class="chapter-item expanded "><a href="../arch/arm64.html"><strong aria-hidden="true">9.2.</strong> arm64</a></li><li class="chapter-item expanded "><a href="../arch/armv7.html"><strong aria-hidden="true">9.3.</strong> armv7</a></li><li class="chapter-item expanded "><a href="../arch/riscv.html"><strong aria-hidden="true">9.4.</strong> riscv</a></li></ol></li></ol>
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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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