Keyword comment Xcode with definition and example

HeaderDoc

<H2> HeaderDoc Tags Common to All Comment Types </H2>
The tags in the table below can be used in any comment for any data type, function, header, or class.

* @abstract -> A short string that briefly describes a function, data type, and so on. This should not contain multiple lines (because it will look odd in the mini-TOCs). Save the detailed descriptions for the discussion tag.
  usage in: block. (single short sentence recommended)
  
* @apiuid -> Overrides the API UID (apple_ref) associated with this comment.
Note that very little checking is performed on this string. Thus, this tag has the potential to seriously break your output if used incorrectly. It is primarily provided for resolving symbol collisions that are otherwise unavoidable, and is generally discouraged.
  usage in: attribute. Must contain no spaces, and must be a valid API reference. See “Symbol Markers for HTML-Based Documentation” for details.
  
  
  Link Apple guide: https://developer.apple.com/library/mac/documentation/DeveloperTools/Conceptual/HeaderDoc/tags/tags.html