std::weakly_incrementable(3)

NAME
std::weakly_incrementable - std::weakly_incrementable

Synopsis
   Defined in header <iterator>
   template<class I>
   concept weakly_incrementable =
   std::movable<I> &&
   requires(I i) { (since
   typename std::iter_difference_t<I>; C++20)
   requires /*is-signed-integer-like*/<std::iter_difference_t<I>>;
   { ++i } -> std::same_as<I&>; // not required to be equality-preserving
   i++; // not required to be equality-preserving
   };
   where /*is-signed-integer-like*/<I> is true if and only if I is a
   signed-integer-like type (see below).
   This concept specifies requirements on types that can be incremented with the pre-
   and post-increment operators, but those increment operations are not necessarily
   equality-preserving, and the type itself is not required to be
   std::equality_comparable.
   For std::weakly_incrementable types, a == b does not imply that ++a == ++b.
   Algorithms on weakly incrementable types must be single-pass algorithms. These
   algorithms can be used with istreams as the source of the input data through
   std::istream_iterator.
  Semantic requirements
   I models std::weakly_incrementable only if, for an object i of type I:
     * The expressions ++i and i++ have the same domain,
     * If i is incrementable, then both ++i and i++ advance i, and
     * If i is incrementable, then std::addressof(++i) == std::addressof(i).
  Integer-like types
   An integer-like type is an (possibly cv-qualified) integer type (except for cv bool)
   or an implementation-provided (not user-provided) class that behaves like an integer
   type, including all operators, implicit conversions, and std::numeric_limits
   specializations. If an integer-like type represents only non-negative values, it is
   unsigned-integer-like, otherwise it is signed-integer-like.
  Defect reports
   The following behavior-changing defect reports were applied retroactively to
   previously published C++ standards.
      DR Applied to Behavior as published Correct behavior
   LWG 3467 C++20 bool was considered as an integer-like type excluded
   P2325R3 C++20 default_initializable was required not required

See also
   incrementable specifies that the increment operation on a weakly_incrementable type
   (C++20) is equality-preserving and that the type is equality_comparable
                 (concept)