std::underflow_error(3) | C++ Standard Libary | std::underflow_error(3) |
NAME¶
std::underflow_error - std::underflow_error
Synopsis¶
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).
std-underflow error-inheritance.svg
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)
underflow_error( const underflow_error& other ); (until C++11)
underflow_error( const underflow_error& other ) (3) (since
C++11)
noexcept;
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 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)
2022.07.31 | http://cppreference.com |