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std::future_errc

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std::future_errc

Non-member functions

make_error_code

make_error_condition

Helper classes

is_error_code_enum

Defined in header <future>

enum class future_errc {

broken_promise = /* implementation-defined */,
future_already_retrieved = /* implementation-defined */,
promise_already_satisfied = /* implementation-defined */,
no_state = /* implementation-defined */

};

(since C++11)

The scoped enumeration std::future_errc defines the error codes reported by std::future and related classes in std::future_error exception objects. Only four error codes are required, although the implementation may define additional error codes. Because the appropriate specialization of std::is_error_code_enum is provided, values of type std::future_errc are implicitly convertible to std::error_code .

All error codes are distinct and non-zero.

Contents

[edit] Member constants

Enumerator Meaning

broken_promise the asynchronous task abandoned its shared state

future_already_retrieved the contents of shared state were already accessed through std::future

promise_already_satisfied attempt to store a value in the shared state twice

no_state attempt to access std::promise or std::future without an associated shared state

[edit] Non-member functions

make_error_code(std::future_errc)

(C++11)

constructs a future error code
(function) [edit]

make_error_condition(std::future_errc)

(C++11)

constructs a future error_condition
(function) [edit]

[edit] Helper classes

is_error_code_enum<std::future_errc>

(C++11)

extends the type trait std::is_error_code_enum to identify future error codes
(class template) [edit]

[edit] Example

This section is incomplete
Reason: no example

[edit] 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 2056	C++11	`broken_promise` was specified to be zero which is conventionally used to mean "no error"	specified to be non-zero

[edit] See also

(C++11)

holds a platform-dependent error code
(class) [edit]

error_condition

(C++11)

holds a portable error code
(class) [edit]

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