std::bad_alloc

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Compiler support
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Language
Standard library
Standard library headers
Named requirements
Feature test macros(C++20)
Language support library
Concepts library(C++20)
Diagnostics library
Memory management library
Metaprogramming library(C++11)
General utilities library
Containers library
Iterators library
Ranges library(C++20)
Algorithms library
Strings library
Text processing library
Numerics library
Date and time library
Input/output library
Filesystem library(C++17)
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Execution control library(C++26)
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[edit]

Utilities library

Language support

Type support (basic types, RTTI)

Library feature-test macros(C++20)

Program utilities

Variadic functions

initializer_list

(C++11)

is_constant_evaluated

(C++20)

is_within_lifetime

(C++26)

source_location

(C++20)

Coroutine support(C++20)

Contract support(C++26)

Three-way comparison

three_way_comparablethree_way_comparable_with

(C++20)(C++20)

strong_ordering

(C++20)

weak_ordering

(C++20)

partial_ordering

(C++20)

common_comparison_category

(C++20)

compare_three_way_result

(C++20)

(C++20)

(C++20)

(C++20)

(C++20)

compare_strong_order_fallback

(C++20)

compare_weak_order_fallback

(C++20)

compare_partial_order_fallback

(C++20)

is_eqis_ltis_lteq

(C++20)(C++20)(C++20)

is_neqis_gtis_gteq

(C++20)(C++20)(C++20)

General utilities

Function objects
Bit manipulation(C++20)
C-style bit manipulation(C++26)
bitset
hash (C++11)

Relational operators(deprecated in C++20)

rel_ops::operator!=rel_ops::operator>

rel_ops::operator<=rel_ops::operator>=

Integer comparison functions

cmp_equalcmp_lesscmp_less_than

(C++20)(C++20)(C++20)

cmp_not_equalcmp_greatercmp_greater_than

(C++20)(C++20)(C++20)

in_range

(C++20)

Swap andtype operations

swap
ranges::swap (C++20)
exchange (C++14)
declval (C++11)
to_underlying (C++23)

forward (C++11)
forward_like (C++23)
move (C++11)
move_if_noexcept (C++11)
as_const (C++17)

Common vocabulary types

pair
tuple (C++11)
optional (C++17)
any (C++17)
variant (C++17)

tuple_size (C++11)
tuple_element (C++11)
apply (C++17)
make_from_tuple (C++17)
expected (C++23)

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Memory management library

voidify

(exposition only*)

Allocators

allocator
allocator_traits (C++11)
allocation_result (C++23)
scoped_allocator_adaptor (C++11)
pmr::polymorphic_allocator (C++17)

allocator_arg (C++11)
uses_allocator (C++11)
uses_allocator_construction_args (C++20)
make_obj_using_allocator (C++20)
uninitialized_construct_using_allocator (C++20)

Uninitialized memory algorithms

uninitialized_copy
uninitialized_fill
uninitialized_move (C++17)
uninitialized_copy_n (C++11)
uninitialized_fill_n
uninitialized_move_n (C++17)
construct_at (C++20)

uninitialized_default_construct (C++17)
uninitialized_value_construct (C++17)
destroy (C++17)
uninitialized_default_construct_n (C++17)
uninitialized_value_construct_n (C++17)
destroy_n (C++17)
destroy_at (C++17)

Constrained uninitialized memory algorithms

ranges::uninitialized_copy (C++20)
ranges::uninitialized_fill (C++20)
ranges::uninitialized_move (C++20)
ranges::uninitialized_copy_n (C++20)
ranges::uninitialized_fill_n (C++20)
ranges::uninitialized_move_n (C++20)
ranges::construct_at (C++20)

ranges::uninitialized_default_construct (C++20)
ranges::uninitialized_value_construct (C++20)
ranges::destroy (C++20)
ranges::uninitialized_default_construct_n (C++20)
ranges::uninitialized_value_construct_n (C++20)
ranges::destroy_n (C++20)
ranges::destroy_at (C++20)

Memory resources

pmr::memory_resource (C++17)
pmr::get_default_resource (C++17)
pmr::set_default_resource (C++17)
pmr::new_delete_resource (C++17)
pmr::pool_options (C++17)

pmr::null_memory_resource (C++17)
pmr::synchronized_pool_resource (C++17)
pmr::unsynchronized_pool_resource (C++17)
pmr::monotonic_buffer_resource (C++17)

Explicit lifetime management
start_lifetime_as (C++23)
start_lifetime_as_array (C++23)

Types for composite class design
indirect (C++26)
polymorphic (C++26)

Uninitialized storage(until C++20)

raw_storage_iterator (until C++20*)
get_temporary_buffer (until C++20*)

return_temporary_buffer (until C++20*)

Garbage collector support(until C++23)

declare_reachable (C++11)(until C++23)
declare_no_pointers (C++11)(until C++23)
pointer_safety (C++11)(until C++23)

undeclare_reachable (C++11)(until C++23)
undeclare_no_pointers (C++11)(until C++23)
get_pointer_safety (C++11)(until C++23)

Low level memory
management

operator newoperator new[]

operator deleteoperator delete[]

(C++11)

bad_alloc

(C++11)

(C++17)

(C++20)

(C++17)

(C++11)

(C++11)

(C++11)

(until C++17*)

(C++11)

(C++17)

(C++26)

(C++26)

enable_shared_from_this

(C++11)

(C++11)

(C++11)

(C++23)

(C++23)

(C++11)

(C++20)

(C++11)

(C++11)

(C++20)

is_sufficiently_aligned

(C++26)

C Library

malloc
calloc
realloc

free
aligned_alloc (C++17)

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Low level memory management

Functions
operator newoperator new[]
operator deleteoperator delete[]
get_new_handler (C++11)
set_new_handler
Classes
bad_alloc
bad_array_new_length (C++11)
align_val_t (C++17)
Types
new_handler
Objects
nothrow
destroying_delete (C++20)
Object access
launder (C++17)

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Defined in header`<new>`
class bad_alloc:publicstd::exception

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

Inheritance diagram

[edit]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) (constexpr since C++26)
		(2)
bad_alloc(const bad_alloc& other)throw();				(until C++11)
bad_alloc(const bad_alloc& other)noexcept;				(since C++11) (constexpr since C++26)

Constructs a newbad_alloc object with an implementation-defined null-terminated byte string which is accessible throughwhat().

1) Default constructor.

2) Copy constructor.If*this andother both have dynamic typestd::bad_alloc thenstd::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) (constexpr since C++26)

Assigns the contents with those ofother.If*this andother both have dynamic typestd::bad_alloc thenstd::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

virtualconstchar* what()constthrow();		(until C++11)
virtualconstchar* what()constnoexcept;		(since C++11) (constexpr since C++26)

Returns the explanatory string.

Return value

Pointer to an implementation-defined null-terminated string with explanatory information. The string is suitable for conversion and display as astd::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.

The returned string is encoded with the ordinary literal encoding during constant evaluation.

(since C++26)

Notes

Implementations are allowed but not required to overridewhat().

Inherited fromstd::exception

Member functions

(destructor) [virtual]	destroys the exception object (virtual public member function of`std::exception`)[edit]
what [virtual]	returns an explanatory string (virtual public member function of`std::exception`)[edit]

[edit]Notes

Feature-test macro	Value	Std	Feature
`__cpp_lib_constexpr_exceptions`	`202411L`	(C++26)	constexpr for exception types

[edit]Example

Run this code

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