std::iostream_category (3) Linux Manual Page

std::iostream_category – std::iostream_category

Synopsis

Defined in header <ios>
const std::error_category& iostream_category() noexcept; (since C++11)

Obtains a reference to the static error category object for iostream errors. The object is required to override the virtual function error_category::name() to return a pointer to the string "iostream". It is used to identify error codes provided in the exceptions of type std::ios_base::failure.

Parameters

(none)

Return value

A reference to the static object of unspecified runtime type, derived from std::error_category.

Example

// Run this code

#include <iostream>

#include <fstream>
int main()

{
    std::ifstream f("doesn't exist");
    try {
        f.exceptions(f.failbit);
    } catch (const std::ios_base::failure &e) {
        std::cout << "Caught an ios_base::failure.\n"
                  << "Error code: " << e.code().value()
                  << " (" << e.code().message() << ")\n"
                  << "Error category: " << e.code().category().name() << '\n';
    }
}

Possible output:

  Caught an ios_base::failure.
  Error code: 1 (unspecified iostream_category error)
  Error category: iostream

See also

        stream exception
failure (public member class of std::ios_base)
io_errc the IO stream error codes
        (enum)
(C++11)