I couldn't find any discussion about this, but I have noticed that the documentation often completely neglects to mention the namespaces used or just mentions somewhere which using namespace directives should be used instead of documenting the namespaces of individual symbols. To me it would seem best to use explicit namespace specification in all example code and reference documentation. However, in example code where this is unsuitable (e.g. boost::placeholders::_1), the required using declarations and directives should be documented along with which symbols they are used for. Adding the namespace information to the documentation increases clarity because it instantly tells the reader which symbols are part of the library and which are part of the example code. Additionally, a number of Boost libraries already use the same symbol names in their respective namespaces, so assuming a large collection of using namespace directives is a bad practice. Documenting the header files to use and the libraries to link is another similar issue, but the problem is not as severe as it is with namespaces.