xref: /third_party/rust/crates/rustix/src/mm/madvise.rs (revision b8a62b91)
1//! The `madvise` function.
2//!
3//! # Safety
4//!
5//! `madvise` operates on a raw pointer. Some forms of `madvise` may
6//! mutate the memory or have other side effects.
7#![allow(unsafe_code)]
8
9use crate::{backend, io};
10use core::ffi::c_void;
11
12pub use backend::mm::types::Advice;
13
14/// `posix_madvise(addr, len, advice)`—Declares an expected access pattern
15/// for a memory-mapped file.
16///
17/// # Safety
18///
19/// `addr` must be a valid pointer to memory that is appropriate to
20/// call `posix_madvise` on. Some forms of `advice` may mutate the memory
21/// or evoke a variety of side-effects on the mapping and/or the file.
22///
23/// # References
24///  - [POSIX]
25///  - [Linux `madvise`]
26///  - [Linux `posix_madvise`]
27///
28/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/posix_madvise.html
29/// [Linux `madvise`]: https://man7.org/linux/man-pages/man2/madvise.2.html
30/// [Linux `posix_madvise`]: https://man7.org/linux/man-pages/man3/posix_madvise.3.html
31#[inline]
32#[doc(alias = "posix_madvise")]
33pub unsafe fn madvise(addr: *mut c_void, len: usize, advice: Advice) -> io::Result<()> {
34    backend::mm::syscalls::madvise(addr, len, advice)
35}
36