libc++ Spaceship Operator Status (operator<=>)

Overview

This document contains the status of the C++20 spaceship operator support in libc++. It is used to track both the status of the sub-projects of the effort and who is assigned to these sub-projects. This is imperative to effective implementation so that work is not duplicated and implementors are not blocked by each other.

If you are interested in contributing to this effort, please send a message to the #libcxx channel in the LLVM discord. Please do not start working on any of the assigned items below.

Sub-Projects in the Implementation Effort

Section

Description

Dependencies

Assignee

Complete

None

Ruslan Arutyunyan

Complete

None

Arthur O’Dwyer

Complete

[cmp.concept]

Kent Ross

Complete

[cmp.concept]

Arthur O’Dwyer

Complete

None

Arthur O’Dwyer

Complete 1

[comparisons.three.way]

Adrian Vogelsgesang

In Progress

None

Adrian Vogelsgesang

Complete

[comparisons.three.way]

Chuanqi Xu

Complete

[expos.only.func]

Kent Ross

Complete

[comparisons.three.way]

Adrian Vogelsgesang

Complete

None

Adrian Vogelsgesang

Complete

[expos.only.func]

Kent Ross

Complete

optional
nullopt

None

Kent Ross

In Progress

None

Kent Ross

Complete

[comparisons.three.way]

Adrian Vogelsgesang

Complete

[comparisons.three.way]

Adrian Vogelsgesang

Complete

None

Adrian Vogelsgesang

Complete

None

Mark de Wever

Complete

None

Mark de Wever

Complete

stacktrace_entry

None

Unassigned

Not Started

basic_stacktrace

[alg.three.way]

Unassigned

Not Started

None

Mark de Wever

Complete

None

Mark de Wever

Complete

[expos.only.func]

Adrian Vogelsgesang

In Progress

deque

[expos.only.func]

Unassigned

Not Started

forward_list

[expos.only.func]

Unassigned

Not Started

list

[expos.only.func]

Unassigned

Not Started

[expos.only.func]

Adrian Vogelsgesang

In Progress

map
multimap

[expos.only.func]

Unassigned

Not Started

multiset
set

[expos.only.func]

Unassigned

Not Started

queue

None

Unassigned

Not Started

stack

None

Unassigned

Not Started

None

Mikhail Maltsev

Complete

move_iterator

None

Unassigned

Not Started

counted_iterator

None

Unassigned

Not Started

[concepts.cmp]

Arthur O’Dwyer

Complete

[concepts.cmp]

Arthur O’Dwyer

Complete

ranges::elements_view::iterator

[concepts.cmp]

Hui Xie

Complete

chrono::duration

None

Mark de Wever

Not Started

chrono::time_point

None

Mark de Wever

Not Started

None

Mark de Wever

Complete

chrono::time_zone
chrono::leap_second
chrono::time_zone_link

A <chrono> implementation

Unassigned

Not Started

None

Adrian Vogelsgesang

Complete

None

Adrian Vogelsgesang

Complete

None

Adrian Vogelsgesang

Complete

sub_match

None

Mark de Wever

In Progress

None

Adrian Vogelsgesang

Complete

Note

1

std::strong_order(long double, long double) is not yet implemented.

Misc. Items and TODOs

(Note: files with required updates will contain the TODO at the beginning of the list item so they can be easily found via global search.)

Paper and Issue Status

Number

Name

Status

First released version

P1614R2

The Mothership has Landed

In Progress

P2404R0

Relaxing equality_comparable_with’s, totally_ordered_with’s, and three_way_comparable_with’s common reference requirements to support move-only types

LWG3330

Include <compare> from most library headers

Complete

13.0

LWG3347

std::pair<T, U> now requires T and U to be less-than-comparable

Nothing To Do

LWG3350

Simplify return type of lexicographical_compare_three_way

Nothing To Do

LWG3360

three_way_comparable_with is inconsistent with similar concepts

Nothing To Do

LWG3380

common_type and comparison categories

Nothing To Do

LWG3395

Definition for three-way comparison needs to be updated

Nothing To Do