# Sequencer

[req.sequencer]

A type S satisfies Sequencer if it meets the following requirements:

Sequencer Requirements: Pseudo-Signature, Semantics

S::S(const S&)

  Copy constructor.

S::~S()

  Destructor.

size_t S::operator()(const T &v)

  Requirements: The type `T` must be the same as the template type argument `T` of the `sequencer_node` instance in which the `S` object is passed during construction.

  Returns the sequence number for the provided message `v`.

See also:

- sequencer_node class