std::bad_alloc

 

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operator newoperator new[]

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bad_alloc

bad_array_new_length (C++11)

align_val_t (C++17)

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destroying_delete (C++20)

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launder (C++17)

 

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.

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

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

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

See also

operator newoperator new[]

allocation functions (function)