std::error_code::message (3) - Linux Manuals
std::error_code::message: std::error_code::message
NAME
std::error_code::message - std::error_code::message
Synopsis
std::string message() const; (since C++11)
Returns the message corresponding to the current error value and category.
Equivalent to category().message(value()).
Parameters
(none)
Return value
The error message corresponding to the current error value and category.
Exceptions
(none)