NAME

std::domain_error - std::domain_error

Synopsis

Defined in header <stdexcept>
class domain_error;

Defines a type of object to be thrown as exception. It may be used by the
implementation to report domain errors, that is, situations where the inputs are
outside of the domain on which an operation is defined.

The standard library components do not throw this exception (mathematical functions
report domain errors as specified in math_errhandling). Third-party libraries,
however, use this. For example, boost.math throws std::domain_error if
boost::math::policies::throw_on_error is enabled (the default setting).

std-domain error-inheritance.svg

Inheritance diagram

Member functions

constructor constructs a new domain_error object with the given message
(public member function)
operator= replaces the domain_error object
(public member function)
what returns the explanatory string
(public member function)

std::domain_error::domain_error

domain_error( const std::string& what_arg ); (1)
domain_error( const char* what_arg ); (2) (since C++11)
domain_error( const domain_error& other ); (3) (until C++11)
domain_error( const domain_error& other ) noexcept; (since C++11)

1-2) Constructs the exception object with what_arg as explanatory string that can be
accessed through what().
3) Copy constructor.
If *this and other both have dynamic type std::domain_error then std::strcmp(what(),
other.what()) == 0.
(since C++11)

Parameters

what_arg - explanatory string
other - another exception object to copy

Exceptions

1-2) May throw std::bad_alloc

Notes

Because copying std::domain_error is not permitted to throw exceptions, this message
is typically stored internally as a separately-allocated reference-counted string.
This is also why there is no constructor taking std::string&&: it would have to copy
the content anyway.

std::domain_error::operator=

domain_error& operator=( const domain_error& other ); (until C++11)
domain_error& operator=( const domain_error& other ) noexcept; (since C++11)

Assigns the contents with those of other.
If *this and other both have dynamic type std::domain_error then std::strcmp(what(),
other.what()) == 0 after assignment.
(since C++11)

Parameters

other - another exception object to assign with

Return value

*this

std::domain_error::what

virtual const char* what() const throw(); (until C++11)
virtual const char* what() const noexcept; (since C++11)

Returns the explanatory string.

Parameters

(none)

Return value

Pointer to a null-terminated string with explanatory information. The string is
suitable for conversion and display as a std::wstring. The pointer is guaranteed to
be valid at least until the exception object from which it is obtained is destroyed,
or until a non-const member function (e.g. copy assignment operator) on the
exception object is called.

Notes

Implementations are allowed but not required to override what().

Inherited from std::logic_error

Inherited from std::exception

Member functions

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