Boost
C++ Libraries
...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Constructor.
url();
Default constructed urls contain a zero-length string. This matches the grammar for a relative-ref with an empty path and no query or fragment.
url u;
this->empty() == true
Constant.
Throws nothing.
relative-ref = relative-part [ "?" query ] [ "#" fragment ]