The following referenced document is indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

• ISO/IEC 14882:—¹, Programming Languages — C++
• RFC 2781, UTF-16, an encoding of ISO 10646

ISO/IEC 14882:— is herein called the C++ Standard. References to clauses within the C++ Standard are written as "C++14 §3.2". The library described in ISO/IEC 14882:— clauses 17–30 is herein called the C++ Standard Library.

Unless otherwise specified, the whole of the C++ Standard's Library introduction (C++14 §17) is included into this Technical Specification by reference.

Since the extensions described in this technical specification are experimental and not part of the C++ standard library, they should not be declared directly within namespace std. Unless otherwise specified, all components described in this technical specification either:

• modify an existing interface in the C++ Standard Library in-place,
• are declared in a namespace whose name appends ::experimental::fundamentals_v1 to a namespace defined in the C++ Standard Library, such as std or std::chrono, or
• are declared in a subnamespace of a namespace described in the previous bullet, whose name is not the same as an existing subnamespace of namespace std.

Each header described in this technical specification shall import the contents of std::experimental::fundamentals_v1 into std::experimental as if by

namespace std {
  namespace experimental {
    inline namespace fundamentals_v1 {}
  }
}