title: VS 2008 C++ build output?
body: <p>Why when I watch the build output from a VC++ project in VS do I see:</p>
  
  <blockquote>
    <p>1>Compiling...<br>
    1>a.cpp<br>
    1>b.cpp<br>
    1>c.cpp<br>
    1>d.cpp<br>
    1>e.cpp<br>
    [etc...]<br>
    1>Generating code...<br>
    1>x.cpp<br>
    1>y.cpp<br>
    [etc...]</p>
  </blockquote>
  
  <p>The output looks as though several compilation units are being handled before any code is generated.  Is this really going on?  I'm trying to improve build times, and by using pre-compiled headers, I've gotten great speedups for each ".cpp" file, but there is a relatively long pause during the "Generating Code..." message.  I do not have "Whole Program Optimization" nor "Link Time Code Generation" turned on.  If this is the case, then why?  Why doesn't VC++ compile each ".cpp" individually (which would include the code generation phase)?  If this isn't just an illusion of the output, is there cross-compilation-unit optimization potentially going on here?  There don't appear to be any compiler options to control that behavior (I know about WPO and LTCG, as mentioned above).</p>
  
  <p><strong>EDIT:</strong><br>
  The build log just shows the ".obj" files in the output directory, one per line.  There is no indication of "Compiling..." vs. "Generating code..." steps.</p>
  
  <p><strong>EDIT:</strong><br>
  I have confirmed that this behavior has nothing to do with the "maximum number of parallel project builds" setting in <em>Tools -> Options -> Projects and Solutions -> Build and Run</em>.  Nor is it related to the <em>MSBuild project build output verbosity</em> setting.  Indeed if I cancel the build before the "Generating code..." step, none of the ".obj" files will exist for the most recent set of "compiled" files.  This implies that the compiler truly is handling multiple translation units together.  Why is this?</p>