title: VS 2008: Fatal error C1083: Cannot open include file: ...: Invalid argument
body: <p>I've seen lots of questions about Fatal Error C1083 "No such file or directory", but in my case I am seeing "Invalid argument".</p>
  
  <p>I am on 32-bit Windows trying to compile some C++ code which uses Boost. This used to work, so something in our setup must've changed, but the error is odd enough that I'm having trouble tracking it down.</p>
  
  <p>I am using the CL compiler on the command line via CMake/jom. The exact error is:</p>
  
  <pre><code>c:\path\to\my\boost\installation\boost/math/constants/constants.hpp(12): fatal error C1083: Cannot open include file: 'boost/math/tools/precision.hpp': Invalid argument
  </code></pre>
  
  <p>constants.hpp looks fine, and unsurprisingly has the following as line 12:</p>
  
  <pre><code>#include &lt;boost/math/tools/precision.hpp&gt;
  </code></pre>
  
  <p>The invocation of <code>cl</code> contains <code>-IC:\path\to\boost\include</code>, and this is late in the compile of a big project which includes other boost headers. The problem seems to come and go, and the last time I saw it, it was at an include of afxwin.h, I think. But it's always "Invalid Argument".</p>
  
  <p>Thanks in advance for any help, this one is driving us crazy.</p>