Documenting namespaces with Doxygen

Question

I'm having issues with Doxygen recognizing namespaces and modules. I believe the issue surrounds whether to place the \addtogroup within the namespace or outside the namespace.

Example 1, outside the namespace:

/*!
 *  \addtogroup Records
 *  @{
 */

//! Generic record interfaces and implementations
namespace Records
{

  //! Describes the record interface  
  class Interface;

} // End namespace Records

/*! @} End of Doxygen Groups*/

Example 2 - within namespace

//! Generic record interfaces and implementations
namespace Records
{
/*!
 *  \addtogroup Records
 *  @{
 */


  //! Describes the record interface  
  class Interface;

/*! @} End of Doxygen Groups*/

} // End namespace Records

I would like the namespace Records to appear under the Doxygen Namespaces tab and indirectly under the Modules tab. Clicking on the item in the Namespaces page should produce a page containing Records::Interface. Clicking on the item in the Modules tab should also produce a page containing Records::Interface.

In my Doxygen documentation, I have items missing from Namespaces tab that are in Modules and vice-versa, due to my inconsistency resulting from this dilemma.

So which is the proper method, Example 1 or Example 2? {The Doxygen manual is not clear on this topic.}
Doxygen: \addtogroup
Doxygen: documenting namespaces

Answer 1

I have performed an experiment using Doxygen and the two examples and here are the results. The class names in the examples have been renamed to avoid confusion with Doxygen.

Example 1, Outside Namespace

/*!
 *  \addtogroup Records
 *  @{
 */

//! Generic record interfaces and implementations
namespace Records
{

  //! Describes the record interface  
  class Interface;

} // End namespace Records

/*! @} End of Doxygen Groups*/

Doxygen Results:

Click on Modules button (in the main bar).
Click on "Records" module in the window.

Example 2: Within Namespace (class renamed to Fields)

//! Generic record interfaces and implementations
namespace Fields
{
/*!
 *  \addtogroup Fields
 *  @{
 */


  //! Describes the record interface  
  class Interface;

/*! @} End of Doxygen Groups*/

} // End namespace Fields

Doxygen Results:

Click on Modules button (in the main bar).
Click on "Records" module in the window.

Summary

The location of Doxygen \addtogroup command has different results depending on whether it is located within a namespace definition or outside. When declared outside of a namespace, the Doxygen Modules tab will show the namespace, as shown in Example 1 above. When the \addtogroup command is placed inside a namespace, the Doxygen Modules tab will not display the namespaces as shown in Example 2 above. If you want your namespace to be listed in the Doxygen Modules tab, locate the \addtogroup command outside of the namespace.

Answer 2

As an alternative, you could also use \ingroupRecords in the namespace documentation:

/**
 * \defgroup Records Title for records module
 * @brief Short doc of Records
 *
 * Long doc of Records.
 */

/**
 * @brief Generic record interfaces and implementations
 *
 * \ingroup Records
 */
namespace Records {
    /// Describes the record interface  
    class Interface;

} /* namespace Records */