title: Simplest driver with visual studio wdk
body: <p>I'm trying to create a simplest "hello world" driver in Visual Studio 2012 with WDK.
  The code of Device.c file is this:</p>
  
  <p><code>#include &lt;ntddk.h&gt;</code></p>
  
  <pre><code>NTSTATUS DriverEntry(PDRIVER_OBJECT DriverObject, PUNICODE_STRING RegistryPath)
  {
      DbgPrint("Hello, World");
  
      return STATUS_SUCCESS;
  }
  </code></pre>
  
  <p>When building there's an error:</p>
  
  <pre><code>1&gt;Driver.c(3): error C2220: warning treated as error - no 'object' file generated
  1&gt;Driver.c(3): warning C4100: 'RegistryPath' : unreferenced formal parameter
  1&gt;Driver.c(3): warning C4100: 'DriverObject' : unreferenced formal parameter
  2&gt;------ Build started: Project: KMDFSmall Package, Configuration: Win7 Debug x64 ------
  2&gt;C:\Program Files (x86)\Windows Kits\8.0\build\WindowsDriver8.0.common.targets(1347,5): error MSB3030: Could not copy the file "Path\To\Projects\SimpleDriver\x64\Win7Debug\KMDFSmall.sys" because it was not found.
  </code></pre>
  
  <p>What causes these errors?</p>