title: session_start() returns "No such file or directory" directly after creating the session file
body: <p>I'm trying to set the session.save_path on my IIS/PHP via fastcgi server.  So I created a new folder called tmp in my php folder, gave IUSR and IIS_IUSRS full permissions to this folder, and set my session.save_path variable in php.ini to "\tmp".</p>
  
  <p>Upon loading my webpage I get the error:</p>
  
  <pre><code>Warning: session_start(): open(tmp\sess_gp13t5fg969iddfq1lrt3e88o1, O_RDWR) failed: No such file or directory (2)
  </code></pre>
  
  <p>The weird thing is I know it can see the folder because I look in my newly created tmp folder and it actually created the sess_gp13t5fg969iddfq1lrt3e88o1 file right before throwing the error telling me it doesn't exist.  So how can it create the file and then not see it?  What could I be doing wrong?</p>
  
  <p><strong>Update:</strong> If I set session.save_path with an absolute path, it works.  When I give it a relative path of just "\tmp" it no longer works.  Every example I see uses a relative path for the save_path and I personally need to use a relative path.  Why would a relative path cause this issue and how do I fix it?</p>