EntropyEngine::Networking::SharedMemory::PlatformOps

Platform-specific shared memory operations. More…

#include <SharedMemoryPlatform.h>

Public Functions

	Name
void	wakeAll(std::atomic< uint32_t > * addr) Wake all threads waiting on an atomic flag.
void	wake(std::atomic< uint32_t > * addr) Wake threads waiting on an atomic flag.
bool	waitUntilChanged(std::atomic< uint32_t > * addr, uint32_t expected, int timeoutMs) Wait until an atomic flag changes from expected value.
void	unmapRegion(void * ptr, size_t size) Unmap a previously mapped region.
NativeHandle	openRegion(const char * name) Open an existing shared memory region.
void *	mapRegion(NativeHandle handle, size_t size) Map a shared memory region into process address space.
bool	isAvailable() Check if shared memory is available on this platform.
std::string	getLastErrorString() Get the last platform error as a string.
void	destroyRegion(const char * name) Destroy a shared memory region.
NativeHandle	createRegion(const char * name, size_t size) Create a new shared memory region.
void	closeRegion(NativeHandle handle) Close a region handle.

Detailed Description

struct EntropyEngine::Networking::SharedMemory::PlatformOps;

Platform-specific shared memory operations.

All methods are static and thread-safe. Each platform provides its own implementation in SharedMemoryPlatformUnix.cpp or SharedMemoryPlatformWin32.cpp.

Public Functions Documentation

function wakeAll

static void wakeAll(
    std::atomic< uint32_t > * addr
)

Wake all threads waiting on an atomic flag.

Parameters:

addr Address of the atomic flag

function wake

static void wake(
    std::atomic< uint32_t > * addr
)

Wake threads waiting on an atomic flag.

Parameters:

addr Address of the atomic flag

Uses platform-specific futex (Linux), ulock (macOS), or WaitOnAddress (Windows).

function waitUntilChanged

static bool waitUntilChanged(
    std::atomic< uint32_t > * addr,
    uint32_t expected,
    int timeoutMs
)

Wait until an atomic flag changes from expected value.

Parameters:

addr Address of the atomic flag
expected Value to wait for change from
timeoutMs Maximum wait time in milliseconds (-1 for infinite)

Return: true if value changed, false if timed out

Blocks until the value at addr is no longer equal to expected, or timeout expires.

function unmapRegion

static void unmapRegion(
    void * ptr,
    size_t size
)

Unmap a previously mapped region.

Parameters:

ptr Pointer returned by mapRegion
size Size of the mapped region

function openRegion

static NativeHandle openRegion(
    const char * name
)

Open an existing shared memory region.

Parameters:

name Region name (must match createRegion name)

Return: Handle to the opened region, or INVALID_HANDLE_VALUE_SHM on failure

Opens a shared memory region previously created by another process.

function mapRegion

static void * mapRegion(
    NativeHandle handle,
    size_t size
)

Map a shared memory region into process address space.

Parameters:

handle Handle from createRegion or openRegion
size Size of the region to map

Return: Pointer to mapped memory, or nullptr on failure

function isAvailable

static bool isAvailable()

Check if shared memory is available on this platform.

Return: true if shared memory operations are supported

function getLastErrorString

static std::string getLastErrorString()

Get the last platform error as a string.

Return: Error description

Returns a human-readable string for the last platform-specific error.

function destroyRegion

static void destroyRegion(
    const char * name
)

Destroy a shared memory region.

Parameters:

name Region name

Removes the region from the filesystem/namespace. Existing mappings remain valid until unmapped.

function createRegion

static NativeHandle createRegion(
    const char * name,
    size_t size
)

Create a new shared memory region.

Parameters:

name Region name (platform-specific prefixing is handled internally)
size Size of the region in bytes

Return: Handle to the created region, or INVALID_HANDLE_VALUE_SHM on failure

Creates a new shared memory region with the given name. The region is created with read/write permissions for the owner.

function closeRegion

static void closeRegion(
    NativeHandle handle
)

Close a region handle.

Parameters:

handle Handle to close

Does not destroy the region if other processes have it open.

Updated on 2026-01-26 at 17:14:35 -0500