std::future_errc
| Defined in header <future>
|
||
| enum class future_errc { broken_promise = /* 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.
Member constants
| Name | Explanation |
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 |
Non-member functions
| constructs a future error code (function) | |
constructs a future error_condition (function) |
Helper classes
| extends the type trait std::is_error_code_enum to identify future error codes (class template) |
Example
| This section is incomplete Reason: no example |
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 |
See also
| (C++11) |
holds a platform-dependent error code (class) |
| (C++11) |
holds a portable error code (class) |