title: Unresolved external symbols in C++ project
body: <p>This is my situation (I am very new to C++ MFC coding and I am trying to debug an existing application project)</p>
  
  <p>I use this line in my code (in a visual studio 2012 MFC project)</p>
  
  <blockquote>
    <p>CoCreateInstance(CLSID_PortableDeviceValues, NULL,
    CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&amp;x));</p>
  </blockquote>
  
  <p>While I run the project, i get a linker error like this </p>
  
  <blockquote>
    <p>error LNK2001: unresolved external symbol _CLSID_PortableDeviceValues</p>
  </blockquote>
  
  <p>This happens for all the CLSID values that I am referring to in the code. Like this</p>
  
  <blockquote>
    <p>error LNK2001: unresolved external symbol
    _CLSID_PortableDeviceKeyCollection </p>
    
    <p>error LNK2001: unresolved external symbol _IID_IPortableDeviceEventCallback </p>
    
    <p>error LNK2001: unresolved external symbol _CLSID_PortableDeviceManager </p>
    
    <p>error LNK2001: unresolved external symbol _CLSID_PortableDeviceServiceFTM</p>
  </blockquote>
  
  <p>I checked for the declaration of "CLSID_PortableDeviceValues" and it was found in "PortableDeviceTypes.h" and I have imported that library as well. </p>
  
  <p>I do not get any compiler error, but run into the linker errors mentioned above..</p>
  
  <p>Can someone please help me out here. I could not resolve this ..</p>