[Doxygen-users] Documenting macro which are not defined in the code

[Edward D. <eld...@tr...>]

In my library there are is a macro which, if defined at all by the 
end-user, changes the way the code works. I want to include this macro 
in the doxygen documentation to my library. So I add the doxygen comments:

/** @file some_header.hpp
     @brief Some brief file description.

     Some longer file description.
*/

/** @def MYLIB_SOME_MACRO
     @brief When this macro is defined at all, changes the way that xxx 
works.

     When this macro is defined at all xxx works in such and such way
     whereas when this macro is not defined xxx works in so and so way.
*/

Unfortunately because the macro itself is never actually defined in any 
header, when I run doxygen I get output such as:

Somepath/some_header.hpp:7: warning: documentation for unknown define 
MYLIB_SOME_MACRO found.

In other words even though I want to include the documentation for the 
MYLIB_SOME_MACRO macro in my doxygen documentation it is rejected 
because the macro is never actually defined in any of the source files 
which doxygen parses.

is there any way to tell doxygen to include the doxygen comments for the 
macro in its documentation even though the macro is not actually defined 
anywhere ?