Standard library header <stop_token> (C++20)

 

C++

Compiler support

Freestanding and hosted

Language

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Technical specifications

Symbols index

External libraries

 

Standard Library headers

Note: a slash '/' in a revision mark means that the header was deprecated and/or removed.

Language Support
<cstddef> <cstdlib> <version> (C++20) <limits> <climits>	<cfloat> <cstdint> (C++11) <new> <typeinfo>	<source_location> (C++20) <exception> <initializer_list> (C++11)   <compare> (C++20)	<coroutine> (C++20) <csignal> <csetjmp> <cstdarg>
Concepts
<concepts> (C++20)
Diagnostics
<stdexcept>	<cassert>	<cerrno>	<system_error> (C++11)
General utilities
<utility> <memory> <memory_resource> (C++17) <scoped_allocator> (C++11)   <expected> (C++23)	<bitset> <tuple> (C++11) <optional> (C++17) <any> (C++17)	<variant> (C++17) <type_traits> (C++11) <ratio> (C++11) <chrono> (C++11)	<typeindex> (C++11) <functional> <stacktrace> (C++23) <ctime>
Strings
<string> <string_view> (C++17) <cstring>	<charconv> (C++17) <format> (C++20)	<cctype> <cwctype>	<cwchar> <cuchar> (C++11)
Localization
<locale> <clocale>	<codecvt> (C++11/17)
Containers
<span> (C++20) <array> (C++11) <vector>	<deque> <forward_list> (C++11) <list>	<map> <set> <queue>	<unordered_map> (C++11) <unordered_set> (C++11) <stack>
Iterators
<iterator>
Ranges
<ranges> (C++20)
Algorithms
<algorithm>	<execution> (C++17)
Numerics
<complex> <random> (C++11)	<valarray> <numeric>	<bit> (C++20) <numbers> (C++20)	<cfenv> (C++11) <cmath>
Input/Output
<iosfwd> <ios> <iomanip> <streambuf>	<istream> <ostream> <iostream>	<syncstream> (C++20) <spanstream> (C++23) <sstream> <fstream>	<cstdio> <cinttypes> (C++11) <strstream> (C++98/)
Regular expressions
<regex> (C++11)
Filesystem support
<filesystem> (C++17)
Thread support
<thread> (C++11) <atomic> (C++11) <mutex> (C++11)	<shared_mutex> (C++14) <condition_variable> (C++11)   <future> (C++11)	<stop_token> (C++20) <semaphore> (C++20)	<latch> (C++20) <barrier> (C++20)
C compatibility
<cstdbool> (C++11/17/20) <ccomplex> (C++11/17/20)	<ctgmath> (C++11/17/20) <cstdalign> (C++11/17/20)	<ciso646> (until C++20) <stdatomic.h>

 

This header is part of the thread support library.

Classes
stop_token (C++20)	an interface for querying if a std::jthread cancellation request has been made (class)
stop_source (C++20)	class representing a request to stop one or more std::jthreads (class)
stop_callback (C++20)	an interface for registering callbacks on std::jthread cancellation (class template)
nostopstate_t (C++20)	placeholder type for use in stop_source constructor (class)
Constants
nostopstate (C++20)	a std::nostopstate_t instance for use in stop_source constructor (constant)

Synopsis

namespace std {
  // class stop_token
  class stop_token;
 
  // class stop_source
  class stop_source;
 
  // no-shared-stop-state indicator
  struct nostopstate_t {
    explicit nostopstate_t() = default;
  };
  inline constexpr nostopstate_t nostopstate{};
 
  // class stop_callback
  template<class Callback>
  class stop_callback;
}

Class std::stop_token

namespace std {
  class stop_token {
  public:
    // constructors, copy, and assignment
    stop_token() noexcept;
 
    stop_token(const stop_token&) noexcept;
    stop_token(stop_token&&) noexcept;
    stop_token& operator=(const stop_token&) noexcept;
    stop_token& operator=(stop_token&&) noexcept;
    ~stop_token();
    void swap(stop_token&) noexcept;
 
    // stop handling
    [[nodiscard]] bool stop_requested() const noexcept;
    [[nodiscard]] bool stop_possible() const noexcept;
 
    [[nodiscard]]
    friend bool operator==(const stop_token& lhs, const stop_token& rhs) noexcept;
    friend void swap(stop_token& lhs, stop_token& rhs) noexcept;
  };
}

Class std::stop_source

namespace std {
  // no-shared-stop-state indicator
  struct nostopstate_t {
    explicit nostopstate_t() = default;
  };
  inline constexpr nostopstate_t nostopstate{};
 
  class stop_source {
  public:
    // constructors, copy, and assignment
    stop_source();
    explicit stop_source(nostopstate_t) noexcept;
 
    stop_source(const stop_source&) noexcept;
    stop_source(stop_source&&) noexcept;
    stop_source& operator=(const stop_source&) noexcept;
    stop_source& operator=(stop_source&&) noexcept;
    ~stop_source();
    void swap(stop_source&) noexcept;
 
    // stop handling
    [[nodiscard]] stop_token get_token() const noexcept;
    [[nodiscard]] bool stop_possible() const noexcept;
    [[nodiscard]] bool stop_requested() const noexcept;
    bool request_stop() noexcept;
 
    [[nodiscard]] friend bool
    operator==(const stop_source& lhs, const stop_source& rhs) noexcept;
    friend void swap(stop_source& lhs, stop_source& rhs) noexcept;
  };
}

Class template std::stop_callback

namespace std {
  template<class Callback>
  class stop_callback {
  public:
    using callback_type = Callback;
 
    // constructors and destructor
    template<class C>
    explicit stop_callback(const stop_token& st, C&& cb)
        noexcept(is_nothrow_constructible_v<Callback, C>);
    template<class C>
    explicit stop_callback(stop_token&& st, C&& cb)
        noexcept(is_nothrow_constructible_v<Callback, C>);
    ~stop_callback();
 
    stop_callback(const stop_callback&) = delete;
    stop_callback(stop_callback&&) = delete;
    stop_callback& operator=(const stop_callback&) = delete;
    stop_callback& operator=(stop_callback&&) = delete;
 
  private:
    Callback callback;      // exposition only
  };
 
  template<class Callback>
  stop_callback(stop_token, Callback) -> stop_callback<Callback>;
}