rcutils_allocator_t Struct Reference

Encapsulation of an allocator. More...

#include <allocator.h>

Public Attributes
void *(*	allocate )(size_t size, void *state)
	Allocate memory, given a size and the state pointer. More...
void(*	deallocate )(void *pointer, void *state)
	Deallocate previously allocated memory, mimicking std::free(). More...
void *(*	reallocate )(void *pointer, size_t size, void *state)
	Reallocate if possible, otherwise it deallocates and allocates. More...
void *(*	zero_allocate )(size_t number_of_elements, size_t size_of_element, void *state)
	Allocate memory with all elements set to zero, given a number of elemets and their size. More...
void *	state
	Implementation defined state storage. More...

Detailed Description

Encapsulation of an allocator.

The default allocator uses std::malloc(), std::free(), std::calloc(), and std::realloc(). It can be obtained using rcutils_get_default_allocator().

The allocator should be trivially copyable. Meaning that the struct should continue to work after being assignment copied into a new struct. Specifically the object pointed to by the state pointer should remain valid until all uses of the allocator have been made. Particular care should be taken when giving an allocator to functions like rcutils_*_init() where it is stored within another object and used later.

Member Data Documentation

void*(* rcutils_allocator_t::allocate) (size_t size, void *state)

Allocate memory, given a size and the state pointer.

An error should be indicated by returning NULL.

void(* rcutils_allocator_t::deallocate) (void *pointer, void *state)

Deallocate previously allocated memory, mimicking std::free().

Also takes the state pointer.

void*(* rcutils_allocator_t::reallocate) (void *pointer, size_t size, void *state)

Reallocate if possible, otherwise it deallocates and allocates.

Also takes the state pointer.

If unsupported then do deallocate and then allocate. This should behave as std::realloc() does, as opposed to posix's reallocf, i.e. the memory given by pointer will not be free'd automatically if std::realloc() fails. For reallocf-like behavior use rcutils_reallocf(). This function must be able to take an input pointer of NULL and succeed.

void*(* rcutils_allocator_t::zero_allocate) (size_t number_of_elements, size_t size_of_element, void *state)

Allocate memory with all elements set to zero, given a number of elemets and their size.

An error should be indicated by returning NULL.

void* rcutils_allocator_t::state

Implementation defined state storage.

This is passed as the final parameter to other allocator functions.

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The documentation for this struct was generated from the following file:

• include/rcutils/allocator.h