title: How to documenting global dependencies for functions?
body: <p>I've got some C code from a 3rd party vendor (for an embedded platform) that uses global variables (for speed &amp; space optimizations).  I'm documenting the code, converting to <code>Doxygen</code> format.  </p>
  
  <p><strong>How do I put a note in the function documentation that the function requires on global variables and functions?</strong></p>
  
  <p><code>Doxygen</code> has special commands for annotating parameters and return values as describe here:  <a href="http://www.doxygen.nl/manual/commands.html" rel="nofollow noreferrer">Doxygen Special Commands</a>.  I did not see any commands for global variables.</p>
  
  <p>Example C code:</p>
  
  <pre><code>    extern unsigned char data_buffer[]; //!&lt; Global variable.
  
      /*! Returns the next available data byte.
       *  \return Next data byte.
       */
      unsigned char Get_Byte(void)
      {
        static unsigned int index = 0;
        return data_buffer[index++]; //!&lt; Uses global variable.   
      }
  </code></pre>
  
  <p>In the above code, I would like to add Doxygen comments that the function depends on the global variable <code>data_buffer</code>.</p>