pub const fn _IOR<T>(ty: u8, nr: u8) -> Ioctl<*mut T>Expand description
Creates an Ioctl that reads data of type T from the kernel.
By default, a pointer to the data will be passed to ioctl(2), and the kernel will fill the
destination with data.
§Errors
This method will cause a compile-time assertion failure if the size of T exceeds the ioctl
argument size limit.
This typically means that the wrong type T was specified.
§Examples
From linux/random.h:
/* ioctl()'s for the random number generator */
/* Get the entropy count. */
#define RNDGETENTCNT _IOR( 'R', 0x00, int )use std::fs::File;
use std::ffi::c_int;
use linux_ioctl::*;
const RNDGETENTCNT: Ioctl<*mut c_int> = _IOR(b'R', 0x00);
let file = File::open("/dev/urandom")?;
let mut entropy = 0;
unsafe { RNDGETENTCNT.ioctl(&file, &mut entropy)? };
println!("{entropy} bits of entropy in /dev/urandom");