std::underflow_error

 

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Exception handling exception uncaught_exceptionuncaught_exceptions (until C++20)(C++17) exception_ptr (C++11) make_exception_ptr (C++11) current_exception (C++11) rethrow_exception (C++11) nested_exception (C++11) throw_with_nested (C++11) rethrow_if_nested (C++11) Exception handling failures terminate terminate_handler get_terminate (C++11) set_terminate bad_exception unexpected (until C++17) unexpected_handler (until C++17) get_unexpected (C++11)(until C++17) set_unexpected (until C++17) Error codes Error codes errno

Exception categories logic_error invalid_argument domain_error length_error out_of_range runtime_error range_error overflow_error underflow_error tx_exception (TM TS) System error support error_category (C++11) generic_category (C++11) system_category (C++11) error_condition (C++11) errc (C++11) error_code (C++11) system_error (C++11) Assertions assert Stacktrace stacktrace_entry (C++23) basic_stacktrace (C++23)

 

Defined in header <stdexcept>
class underflow_error;

Defines a type of object to be thrown as exception. It may be used to report arithmetic underflow errors (that is, situations where the result of a computation is a subnormal floating-point value)

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

Inheritance diagram

Member functions

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

std::underflow_error::underflow_error

underflow_error( const std::string& what_arg );	(1)
underflow_error( const char* what_arg );	(2)	(since C++11)
	(3)
underflow_error( const underflow_error& other );			(until C++11)
underflow_error( const underflow_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::underflow_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::underflow_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::underflow_error::operator=

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

Assigns the contents with those of other. If *this and other both have dynamic type std::underflow_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::underflow_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::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)