nix::ioctl!

macro_rules! ioctl {
    (bad $name:ident with $nr:expr) => (
        pub unsafe fn $name(fd: $crate::sys::ioctl::libc::c_int,
                            data: *mut u8)
                            -> $crate::Result<$crate::sys::ioctl::libc::c_int> {
            convert_ioctl_res!($crate::sys::ioctl::ioctl(fd, $nr as $crate::sys::ioctl::libc::c_ulong, data))
        }
        );
    (none $name:ident with $ioty:expr, $nr:expr) => (
        pub unsafe fn $name(fd: $crate::sys::ioctl::libc::c_int)
                            -> $crate::Result<$crate::sys::ioctl::libc::c_int> {
            convert_ioctl_res!($crate::sys::ioctl::ioctl(fd, io!($ioty, $nr) as $crate::sys::ioctl::libc::c_ulong))
        }
        );
    (read $name:ident with $ioty:expr, $nr:expr; $ty:ty) => (
        pub unsafe fn $name(fd: $crate::sys::ioctl::libc::c_int,
                            val: *mut $ty)
                            -> $crate::Result<$crate::sys::ioctl::libc::c_int> {
            convert_ioctl_res!($crate::sys::ioctl::ioctl(fd, ior!($ioty, $nr, ::std::mem::size_of::<$ty>()) as $crate::sys::ioctl::libc::c_ulong, val))
        }
        );
    (write $name:ident with $ioty:expr, $nr:expr; $ty:ty) => (
        pub unsafe fn $name(fd: $crate::sys::ioctl::libc::c_int,
                            val: *const $ty)
                            -> $crate::Result<$crate::sys::ioctl::libc::c_int> {
            convert_ioctl_res!($crate::sys::ioctl::ioctl(fd, iow!($ioty, $nr, ::std::mem::size_of::<$ty>()) as $crate::sys::ioctl::libc::c_ulong, val))
        }
        );
    (readwrite $name:ident with $ioty:expr, $nr:expr; $ty:ty) => (
        pub unsafe fn $name(fd: $crate::sys::ioctl::libc::c_int,
                            val: *mut $ty)
                            -> $crate::Result<$crate::sys::ioctl::libc::c_int> {
            convert_ioctl_res!($crate::sys::ioctl::ioctl(fd, iorw!($ioty, $nr, ::std::mem::size_of::<$ty>()) as $crate::sys::ioctl::libc::c_ulong, val))
        }
        );
    (read buf $name:ident with $ioty:expr, $nr:expr; $ty:ty) => (
        pub unsafe fn $name(fd: $crate::sys::ioctl::libc::c_int,
                            val: *mut $ty,
                            len: usize)
                            -> $crate::Result<$crate::sys::ioctl::libc::c_int> {
            convert_ioctl_res!($crate::sys::ioctl::ioctl(fd, ior!($ioty, $nr, len) as $crate::sys::ioctl::libc::c_ulong, val))
        }
        );
    (write buf $name:ident with $ioty:expr, $nr:expr; $ty:ty) => (
        pub unsafe fn $name(fd: $crate::sys::ioctl::libc::c_int,
                            val: *const $ty,
                            len: usize) -> $crate::Result<$crate::sys::ioctl::libc::c_int> {
            convert_ioctl_res!($crate::sys::ioctl::ioctl(fd, iow!($ioty, $nr, len) as $crate::sys::ioctl::libc::c_ulong, val))
        }
        );
    (readwrite buf $name:ident with $ioty:expr, $nr:expr; $ty:ty) => (
        pub unsafe fn $name(fd: $crate::sys::ioctl::libc::c_int,
                            val: *const $ty,
                            len: usize)
                            -> $crate::Result<$crate::sys::ioctl::libc::c_int> {
            convert_ioctl_res!($crate::sys::ioctl::ioctl(fd, iorw!($ioty, $nr, len) as $crate::sys::ioctl::libc::c_ulong, val))
        }
        );
}

Declare a wrapper function around an ioctl.