std::ios_base::failure

 

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Defined in header <ios>
class failure;

The class std::ios_base::failure defines an exception object that is thrown on failure by the functions in the Input/Output library.

std::ios_base::failure may be defined either as a member class of std::ios_base or as a synonym (typedef) for another class with equivalent functionality. (since C++17)

Inheritance diagram	(until C++11)
Inheritance diagram	(since C++11)

Member functions

(constructor)

constructs the exception object (public member function)

std::ios_base::failure::failure

explicit failure( const std::string& message );		(until C++11)
explicit failure( const std::string& message,                   const std::error_code& ec = std::io_errc::stream );		(since C++11)
explicit failure( const char* message,                   const std::error_code& ec = std::io_errc::stream );		(since C++11)

Constructs the exception object using message as explanation string which can later be retrieved using what().

Parameters

message

-

explanatory string

Inherited from std::system_error

Member functions

code	returns error code (public member function of std::system_error)
what [virtual]	returns explanatory string (virtual public member function of std::system_error)

Inherited from std::runtime_error

Inherited from std::exception

Member functions

(destructor) [virtual]	destroys the exception object (virtual public member function of std::exception)
what [virtual]	returns an explanatory string (virtual public member function of std::exception)

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"
                  << "Explanatory string: " << e.what() << '\n'
                  << "Error code: " << e.code() << '\n';
    }
}

Output:

Caught an ios_base::failure.
Explanatory string: ios_base::clear: unspecified iostream_category error
Error code: iostream:1

See also

io_errc (C++11)

the IO stream error codes (enum)