std::underflow_error
Defined in header <stdexcept> |
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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
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(constructor)
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constructs a new underflow_error object with the given message (public member function) |
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operator=
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replaces the underflow_error object (public member function) |
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what
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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) |
what_arg as explanatory string that can be accessed through
what().
*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
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
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[virtual]
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destroys the exception object (virtual public member function of std::exception) |
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[virtual]
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returns an explanatory string (virtual public member function of std::exception) |
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