Boost 1.66 Not Supported for rippled 0.81.0

A warning to developers: rippled versions 0.81.0 and earlier do not compile with the recently-released Boost library version 1.66.0. To compile rippled yourself, Ripple recommends using Boost version 1.65.1. The minimum supported version of Boost is 1.58.0, which is included in the official repositories of Ubuntu 16.04 Xenial.

Compiler Errors

If you try to compile rippled version 0.81.0 with Boost version 1.66.0 or higher, you get compiler errors such as the following:

In file included from src/beast/include/beast/core/detail/type_traits.hpp:13:0,
                 from src/beast/include/beast/core/impl/static_string.ipp:12,
                 from src/beast/include/beast/core/static_string.hpp:1106,
                 from src/beast/include/beast/core/string_param.hpp:13,
                 from src/beast/include/beast/http/fields.hpp:12,
                 from src/beast/include/beast/http/message.hpp:12,
                 from src/ripple/server/Handoff.h:24,
                 from src/ripple/overlay/Overlay.h:26,
                 from src/ripple/app/consensus/RCLConsensus.cpp:39,
                 from src/ripple/unity/app_consensus.cpp:21:
/usr/include/boost/asio/io_service.hpp:27:20: error: conflicting declaration
 ‘typedef class boost::asio::io_context boost::asio::io_service’
 typedef io_context io_service;

If you encounter this issue, please downgrade to Boost version 1.65.1.

Background

Boost 1.66.0 introduces the Boost.Beast library for HTTP and WebSocket connections. The Beast library was built by prolific coder and Ripple alum Vinnie Falco as an add-on to the Boost.Asio library, for use in rippled and other C++ software. Because Beast made its start in the rippled code base, the version already included in rippled conflicts with the version included as part of the Boost library in versions 1.66.0 and higher.

Future Work

Ripple expects to make rippled compatible with Boost 1.66.0 and higher in a future release. At that time, rippled will no longer be compatible with Boost version 1.65.x and lower. Stay tuned to rippled release announcements for updates on this transition.