std:: iostream_category

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

#include <fstream>
#include <iostream>
 
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';
 
    }
}

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

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

See also