Macro nix::request_code_read

macro_rules! request_code_read {
    ($ty:expr, $nr:expr, $sz:expr) => { ... };
}

Generate an ioctl request code for a command that reads.

This is equivalent to the _IOR() macro exposed by the C ioctl API.

You should only use this macro directly if the ioctl you're working with is "bad" and you cannot use ioctl_read!() directly.

The read/write direction is relative to userland, so this command would be userland is reading and the kernel is writing.