Function madvise

pub unsafe fn madvise(
    addr: *const c_void,
    len: usize,
    advice: i32,
) -> Result<(), i32> 

Available on crate feature dep_nc only.

Give advice about use of memory.

Examples

use std::ptr;

// Initialize an anonymous mapping with 4 pages.
let map_length = 4 * nc::PAGE_SIZE;
let ret = unsafe {
    nc::mmap(
        ptr::null(),
        map_length,
        nc::PROT_READ | nc::PROT_WRITE,
        nc::MAP_PRIVATE | nc::MAP_ANONYMOUS,
        -1,
        0,
    )
};
assert!(ret.is_ok());
let addr = ret.unwrap();

// Notify kernel that the third page will be accessed.
let ret = unsafe { nc::madvise(addr.wrapping_add(2 * nc::PAGE_SIZE), nc::PAGE_SIZE, nc::MADV_WILLNEED) };
assert!(ret.is_ok());

let ret = unsafe { nc::munmap(addr, map_length) };
assert!(ret.is_ok());