NAME

std::bad_alloc - std::bad_alloc

Synopsis

Defined in header <new>
class bad_alloc;

std::bad_alloc is the type of the object thrown as exceptions by the allocation
functions to report failure to allocate storage.

std-bad alloc-inheritance.svg

Inheritance diagram

Member functions

constructor constructs a new bad_alloc object
(public member function)
operator= replaces the bad_alloc object
(public member function)
what returns the explanatory string
(public member function)

std::bad_alloc::bad_alloc

bad_alloc() throw(); (until C++11)
bad_alloc() noexcept; (1) (since C++11)
bad_alloc( const bad_alloc& other ) throw(); (2) (until C++11)
bad_alloc( const bad_alloc& other ) noexcept; (since C++11)

Constructs a new bad_alloc object with an implementation-defined null-terminated
byte string which is accessible through what().

1) Default constructor.
2) Copy constructor.
If *this and other both have dynamic type std::bad_alloc then std::strcmp(what(),
other.what()) == 0.
(since C++11)

Parameters

other - another exception object to copy

std::bad_alloc::operator=

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

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

Parameters

other - another exception object to assign with

Return value

*this

std::bad_alloc::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::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)

Example

// Run this code

#include <iostream>
#include <new>

int main()
{
try {
while (true) {
new int[100000000ul];
}
} catch (const std::bad_alloc& e) {
std::cout << "Allocation failed: " << e.what() << '\n';
}
}

Possible output:

Allocation failed: std::bad_alloc