Module rustix::shm

POSIX shared memory

Example

use rustix::fs::{ftruncate, Mode};
use rustix::mm::{mmap, MapFlags, ProtFlags};
use rustix::{io, shm};
use std::mem::size_of;
use std::ptr::null_mut;

// A type describing the data to be shared.
#[repr(C)]
struct MyBufferType {
    // …
}

// Create the shared memory object.
let shm_path = "/rustix-shm-example";
let fd = shm::open(
    shm_path,
    shm::OFlags::CREATE | shm::OFlags::EXCL | shm::OFlags::RDWR,
    Mode::RUSR | Mode::WUSR,
)?;

// Resize the shared memory object to the size of our data.
ftruncate(&fd, size_of::<MyBufferType>() as u64)?;

// Map the shared memory object into our address space.
//
// SAFETY: We're creating a new mapping that's independent of any existing
// memory allocations. There are interesting things to say about *using*
// `ptr`, but that's for another safety comment.
let ptr = unsafe {
    mmap(
        null_mut(),
        size_of::<MyBufferType>(),
        ProtFlags::READ | ProtFlags::WRITE,
        MapFlags::SHARED,
        &fd,
        0,
    )?
};

// Use `ptr`…

// Remove the shared memory object name.
shm::unlink(shm_path)?;

Structs

• Mode
  S_I* constants for use with openat, chmodat, and fchmod.
• OFlags
  O_* constants for use with shm::open.

Functions

• open
  shm_open(name, oflags, mode)—Opens a shared memory object.
• unlink
  shm_unlink(name)—Unlinks a shared memory object.