Why would you use 'extern “C++”'?

Question

In this article the keyword extern can be followed by \"C\" or \"C++\". Why would you use \'extern \"C++\"\'? Is it practical?

Answer 1

Two guesses:

• If you are in a extern "C" block, you can get C++ language linkage again by specifying a nested extern "C++".
• It reserves C++ linkage, because it's the document defining C++. Who is in a better position for defining C++ language linkage than it itself. It also provides for completeness. Same deal as with signed/unsigned.

Read this answer that explains extern "LanguageName" (i.e GCC has extern "Java") aswell.