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.

message(
    status result,
    unsigned version);

Name	Description
`result`	The status-code for the response.
`version`	The HTTP-version.

This member is only available when isRequest == false.