title: Reason for "{return 0;}" or "{;}" in library's .h file
body: <p>I am currently working on a project with some old poorly documented code, and am trying to navigate my way through the various .h files that they have provided complete documentation on the use of all of the functions contained (the definitions are held in .lib and .dll files). One of the .h files has functions the are not only declared, but defined with either simple return statements or empty statements as such</p>
  
  <pre><code>class DLL ExampleLibraryClass {
  public:
      int exampleGetValue() {return 0;}
      void exampleSetValue(Type val) {;}
      void exampleActionFxn() {;}
  };
  </code></pre>
  
  <p>These would be functions that I expect to return current variable states or perform certain actions, which is why this puzzles me.</p>
  
  <p><strong>Additionally:</strong></p>
  
  <ul>
  <li><p>I have used Dependency Walker and found that each function does have a matching definition in a dll.</p></li>
  <li><p>The Keyword DLL has been defined with</p>
  
  <pre><code>#ifndef _PWSDLL_
  #   define _PWSDLL_
  #   define WINCALL  _stdcall
  #   ifdef _USRDLL
  #       define DLL  __declspec(dllexport)
  #   else
  #       define DLL  __declspec(dllimport)
  #   endif
  #endif
  </code></pre>
  
  <p>_USRDLL is not defined and therefore <code>DLL</code> is defined as <code>__declspec(dllimport)</code></p></li>
  </ul>
  
  <p>My question revolves less about the apparent effect of the empty definitions (which do nothing I suppose, and have already been discussed on SO) and more about why the .h file has been written this way and how to utilize the file. Is this a common or known practice? Will the linker still look for definitions to the function in my linked libraries? Are there other pieces of code that I should look for for more clues? Or perhaps in the broadest sense, how should I respond to this?</p>
  
  <p>Many thanks, and please let me know if you need more information to address this, I am unsure what exactly is important in this matter.</p>
  
  <p><strong>EDIT:</strong> Added forgotten return types in example code.</p>
  
  <p><strong>EDIT:</strong> Added note about DLL definition.</p>