title: C++ concat LPCTSTR
body: <p>I am implementing a custom action for a WindowsCE CAB file, and I need to concat a LPCTSTR to get a proper path to an exe.</p>
  
  <p>My custom action receives a LPCTSTR as an argument.</p>
  
  <p>So (pseudocode):</p>
  
  <pre><code>extern "C" codeINSTALL_EXIT MYCUSTOMACTION_API Install_Exit(
      HWND    hwndParent,
      LPCTSTR pszInstallDir,
      WORD    cFailedDirs,
      WORD    cFailedFiles,
      WORD    cFailedRegKeys,
      WORD    cFailedRegVals,
      WORD    cFailedShortcuts
  )
  {
      if (FALSE == LaunchApp(pszInstallDir + "\\MyApp.exe"))
         ::MessageBox(hwndParent, L"Could not launch app!", L"Setup", MB_ICONINFORMATION );
      return codeINSTALL_EXIT_DONE;
  }
  </code></pre>
  
  <p>This is using the imaginary "+" operator, that I would use in my standard language, C#.</p>
  
  <p>I have relatively little experience in C++.  What is the proper way to append a LPCTSTR for my purposes?  The LaunchApp method uses this type as an argument.</p>
  
  <p>Also if I want to display the resulting path (for debugging purposes) in a MessageBox, is there a quick way to convert to a LPCWSTR?</p>