Documentation of memory

( foonathan/memory)

bad_allocation_size Class Reference

Detailed Description

The exception class thrown when an allocation size is bigger than the supported maximum.

This size is either the node, array or alignment parameter in a call to an allocation function. If those exceed the supported maximum returned by max_node_size(), max_array_size() or max_alignment(), one of its derived classes will be thrown or this class if in a situation where the type is unknown. It is derived from std::bad_alloc. Throwing can be prohibited by the handler function.

Even if all parameters are less than the maximum, out_of_memory or a similar exception can be thrown, because the maximum functions return an upper bound and not the actual supported maximum size, since it always depends on fence memory, alignment buffer and the like.
A user should only catch for bad_allocation_size, not the derived classes.
Most checks will only be done if FOONATHAN_MEMORY_CHECK_ALLOCATION_SIZE is true.


using handler = void(*)(const allocator_info &info, std::size_t passed, std::size_t supported)
 The type of the handler called in the constructor of bad_allocation_size. More...

Static Functions

static handler set_handler (handler h)
static handler get_handler ()

Member Functions

 bad_allocation_size (const allocator_info &info, std::size_t passed, std::size_t supported)
const char * what () const noexcept override
const allocator_infoallocator () const noexcept
std::size_t passed_value () const noexcept
std::size_t supported_value () const noexcept


§ handler

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

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

When a bad allocation size is detected and the exception object created, this handler gets called. It is especially useful if exception support is disabled. It gets the allocator_info, the size passed to the function and the supported size (the latter is still an upper bound).

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.


§ bad_allocation_size()

bad_allocation_size ( const allocator_info info,
std::size_t  passed,
std::size_t  supported 
Creates it by passing it the allocator_info, the size passed to the allocation function and an upper bound on the supported size. It also calls the handler to control whether or not it will be thrown.

Member Functions

§ set_handler()

static handler set_handler ( handler  h)
Sets h as the new handler in an atomic operation. A nullptr sets the default handler.
The previous handler. This is never nullptr.

§ get_handler()

static handler get_handler ( )
The current handler. This is never nullptr.

§ what()

const char* what ( ) const
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
The allocator_info passed to it in the constructor.

§ passed_value()

std::size_t passed_value ( ) const
The size or alignment value that was passed to the allocation function which was too big. This is the same value passed to the constructor.

§ supported_value()

std::size_t supported_value ( ) const
An upper bound on the maximum supported size/alignment. It is only an upper bound, values below can fail, but values above will always fail.