std::future_error::future_error (3) Linux Manual Page

std::future_error::future_error – std::future_error::future_error

Synopsis

explicit future_error( std::future_errc ec ); (since C++17)
Constructs a new future error object containing the error code std::make_error_code(ec).

Parameters

ec – error code

Notes

There is no standard-compliant way for the user to construct a future_error prior to C++17. C++11 and C++14 depict an exposition-only public constructor taking a std::error_code, and some implementations provide such a constructor.