iox::mepoo::ShmSafeUnmanagedChunk

This class to safely store a chunk in shared memory. To be able to do so, torn writes/reads need to prevented, since they create Frankenstein objects. Therefore, the class must not be larger than 64 bits and trivially copy-able in case an application dies while writing this and RouDi needs to clean up.

#include <shm_safe_unmanaged_chunk.hpp>

Public Functions

	Name
	ShmSafeUnmanagedChunk() =default
	ShmSafeUnmanagedChunk(SharedChunk chunk) takes a SharedChunk without decrementing the chunk reference counter
SharedChunk	releaseToSharedChunk() Creates a SharedChunk without incrementing the chunk reference counter and invalidates itself.
SharedChunk	cloneToSharedChunk() Creates a SharedChunk with incrementing the chunk reference counter and does not invalidate itself.
bool	isLogicalNullptr() const Checks if the underlying RelativePointerData to the chunk is logically a nullptr.
ChunkHeader *	getChunkHeader() Access to the ChunkHeader of the underlying chunk.
const ChunkHeader *	getChunkHeader() const const access to the ChunkHeader of the underlying chunk
bool	isNotLogicalNullptrAndHasNoOtherOwners() const Checks if the underlying RelativePointerData to the chunk is neither logically a nullptr nor that the chunk has other owner.

Public Functions Documentation

function ShmSafeUnmanagedChunk

ShmSafeUnmanagedChunk() =default

function ShmSafeUnmanagedChunk

ShmSafeUnmanagedChunk(
    SharedChunk chunk
)

takes a SharedChunk without decrementing the chunk reference counter

function releaseToSharedChunk

SharedChunk releaseToSharedChunk()

Creates a SharedChunk without incrementing the chunk reference counter and invalidates itself.

function cloneToSharedChunk

SharedChunk cloneToSharedChunk()

Creates a SharedChunk with incrementing the chunk reference counter and does not invalidate itself.

function isLogicalNullptr

bool isLogicalNullptr() const

Checks if the underlying RelativePointerData to the chunk is logically a nullptr.

Return: true if logically a nullptr otherwise false

function getChunkHeader

ChunkHeader * getChunkHeader()

Access to the ChunkHeader of the underlying chunk.

Return: the pointer to the ChunkHeader of the underlying chunk or nullptr if isLogicalNullptr would return true

function getChunkHeader

const ChunkHeader * getChunkHeader() const

const access to the ChunkHeader of the underlying chunk

Return: the const pointer to the ChunkHeader of the underlying chunk or nullptr if isLogicalNullptr would return true

function isNotLogicalNullptrAndHasNoOtherOwners

bool isNotLogicalNullptrAndHasNoOtherOwners() const

Checks if the underlying RelativePointerData to the chunk is neither logically a nullptr nor that the chunk has other owner.

Return: true if neither logically a nullptr nor other owner chunk owners present, otherwise false

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Updated on 31 May 2022 at 15:29:16 CEST