out_of_memory Class Reference

Detailed Description

The exception class thrown when a low level allocator runs out of memory.

It is derived from std::bad_alloc. This can happen if a low level allocation function like std::malloc() runs out of memory. Throwing can be prohibited by the handler function.

Typedefs
using	handler = void(*)(const allocator_info &info, std::size_t amount)
	The type of the handler called in the constructor of out_of_memory.

Static Functions
static handler	set_handler (handler h)
static handler	get_handler ()

Member Functions
	out_of_memory (const allocator_info &info, std::size_t amount)
const char *	what () const noexcept override
const allocator_info &	allocator () const noexcept
std::size_t	failed_allocation_size () const noexcept

Typedefs

handler

using handler = void (*)(const allocator_info& info, std::size_t amount)

The type of the handler called in the constructor of out_of_memory.

When an out of memory situation is encountered and the exception class created, this handler gets called. It is especially useful if exception support is disabled. It gets the allocator_info and the amount of memory that was tried to be allocated.

Required Behavior:

It can log the error, throw a different exception derived from std::bad_alloc or abort the program. If it returns, this exception object will be created and thrown.

Default Behavior:

On a hosted implementation it logs the error on stderr and continues execution, leading to this exception being thrown. On a freestanding implementation it does nothing.

Note

It is different from std::new_handler; it will not be called in a loop trying to allocate memory or something like that. Its only job is to report the error.

Constructors

out_of_memory()

out_of_memory	(	const allocator_info &	info,
		std::size_t	amount
	)

Effects:

Creates it by passing it the allocator_info and the amount of memory failed to be allocated. It also calls the handler to control whether or not it will be thrown.

Member Functions

set_handler()

static handler set_handler ( handler  h )

static

Effects:

Sets h as the new handler in an atomic operation. A nullptr sets the default handler.

Returns:

The previous handler. This is never nullptr.

get_handler()

static handler get_handler ( )

static

Returns:

The current handler. This is never nullptr.

what()

const char * what ( ) const

overridenoexcept

Returns:

A static NTBS that describes the error. It does not contain any specific information since there is no memory for formatting.

allocator()

const allocator_info & allocator ( ) const

noexcept

Returns:

The allocator_info passed to it in the constructor.

failed_allocation_size()

std::size_t failed_allocation_size ( ) const

noexcept

Returns:

The amount of memory that was tried to be allocated. This is the value passed in the constructor.