可移植的 C++ 标准库 Boost 1.67.0 beta 1 版本发布，Boost 库是一个经过千锤百炼、可移植、提供源代码的 C++ 库，作为标准库的后备，是 C++ 标准化进程的发动机之一，由 C++ 标准委员会库工作组成员发起。
Contract:Contract programming for C++. All contract programming features are supported: Subcontracting, class invariants, postconditions (with old and return values), preconditions, customizable actions on assertion failure (e.g., terminate or throw), optional compilation and checking of assertions, etc, from Lorenzo Caminiti.
HOF:Higher-order functions for C++, from Paul Fultz II.
experimental::detached completion token.
experimental::redirect_error completion token.
experimental::co_spawn facility for integration with the coroutines technical specification.
Added missing const qualifier to
Worked around a parsing error that occurs with some versions of gcc.
Fixed broken code samples in tutorial.
Added new experimental features. (Note that "experimental" features may be changed without notice in subsequent releases.)