C++ single line comments followed by \ transforms in multiline comment

Where is it documented in the C++ Standard the feature that if a line is commented using //some comment\ style (at the end of the line puts \) the comment is transformed to multiline?

Tested with g++ 4.8 and VS 2012

//some interesting stuff\
another interesting stuff\
etc

C++ standard, 2.2 - phases of translation. Phase 2 includes

Each instance of a backslash character (\) immediately followed by a new-line character is deleted, splicing physical source lines to form logical source lines.

and Phase 3 includes

Each comment is replaced by one space character

So the backslash at the end of the line is recognised before comments.

Equivalent phases 2 and 3 for C can be found in C standard (5.1.1.2 Translation phases in my draft).

A \ followed by a new line is eliminated very early in the translation process, before the compiler starts looking for comments and the end of comments, see §2.2, Phases of translation.