# std::stoppable_token

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< cpp‎ | thread

Defined in header `<stop_token>` |  |

template< class Token >

concept stoppable_token =
requires (const Token tok) {
typename /*check-type-alias-exists*/<Token::template callback_type>;
{ tok.stop_requested() } noexcept -> std::same_as <bool>;
{ tok.stop_possible() } noexcept -> std::same_as <bool>;
{ Token(tok) } noexcept; // see implicit expression variations
} &&
std::copyable <Token> &&

std::equality_comparable <Token>;

(since C++26)

Helper templates |  |
template< template<class> class > struct /*check-type-alias-exists*/; // not defined |  | (exposition only*)

The concept `stoppable_token<Token>` specifies the basic interface of a stop token that is `copyable` and `equality_comparable` and allows polling to see if the stop request is possible and whether the request has been made.

### Semantic requirements

| This section is incomplete

### See also

unstoppable_token (C++26) | specifies a stop token that does not allow stopping (concept)

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