title: How to generate CHM with Doxygen and HTML Help Compiler?
body: <p><strong>The short story</strong>:  I can generate a CHM file with Doxygen.  Launching the CHM file, I observe that the Contents and Index tabs do list the pages, namespaces, classes, and members of those classes.  However, clicking on the items in those Contents and Index lists do not display any content.</p>
  
  <p>I am on a computer using Windows 7 Professional SP1, 64-bit.</p>
  
  <p>I use Doxywizard to run Doxygen version 1.8.9.1 on my code.  It correctly generates the HTML output;  the pages, namespaces, classes, and members appear in the documentation.</p>
  
  <p>I then further want to convert the HTML into a compressed HTML (CHM) file.  </p>
  
  <p>I downloaded the Microsoft HTML Help Workshop version 1.31 (i.e., <code>htmlhelp.exe</code> version 4.74.8703 ) from the Microsoft website ( <a href="https://msdn.microsoft.com/en-us/library/windows/desktop/ms669985(v=vs.85).aspx" rel="nofollow">https://msdn.microsoft.com/en-us/library/windows/desktop/ms669985(v=vs.85).aspx</a> ).  I ran the installer.  As the installer was proceeding, a popup message appeared:</p>
  
  <blockquote>
    <p>This computer already has a newer version of HTML Help.</p>
  </blockquote>
  
  <p>However, installation completed successfully.  And, the <code>hhc.exe</code> program is there where I told it to install.</p>
  
  <p>I now specify these relevant Doxygen settings:</p>
  
  <ul>
  <li>Wizard --> Output:
  <ul>
  <li>HTML is checked</li>
  <li>"prepare for compressed HTML (.chm)" option is selected.</li>
  </ul></li>
  <li>Expert --> HTML:
  <ul>
  <li>GENERATE_HTMLHELP = YES</li>
  <li>CHM_FILE = Foo.chm</li>
  <li>HHC_LOCATION = C:\Program Files(x86)\Microsoft\HTML Help Workshop\hhc.exe</li>
  </ul></li>
  </ul>
  
  <p>When I run Doxygen again, it reports an error:</p>
  
  <pre><code>error: failed to run html help compiler on index.hhp
  </code></pre>
  
  <p>The <code>Foo.chm</code> file is generated where expected.  But, as described above, it is missing a lot of content.</p>
  
  <p>I tried running <code>hhc.exe</code> manually on the HHP file generated by Doxygen.  It does not indicate any errors.</p>
  
  <pre><code>C:\Program Files (x86)\Microsoft\HTML Help Workshop&gt;hhc c:\test\html\index.hhp
  Microsoft HTML Help Compiler 4.74.8702
  
  Compiling c:\test\html\Foo.chm
  
  Compile time: 0 minutes, 3 seconds
  292     Topics
  3,855   Local links
  83      Internet links
  0       Graphics
  
  Created c:\test\html\Foo.chm, 259,580 bytes
  Compression decreased file by 1,077,915 bytes.
  </code></pre>
  
  <p>However, the result is the same:  a <code>Foo.chm</code> file that is missing content.</p>
  
  <p>I subsequently found that I had another installation of the HTML Help Workshop on my computer.  But, the <code>hhc.exe</code> was the exact same version.  So, that is not likely the problem.</p>
  
  <p>Can you suggest what else I can try to get all the documentation content to display in the CHM file?</p>