Macro getsockopt_impl 

macro_rules! getsockopt_impl {
    ($name:ident, $level:expr, $flag:path, $ty:ty, $getter:ty) => { ... };
}

Helper for implementing GetSockOpt for a given socket option. See ::sys::socket::GetSockOpt.

This macro aims to help implementing GetSockOpt for different socket options that accept different kinds of data to be use with getsockopt.

Instead of using this macro directly consider using sockopt_impl!, especially if the option you are implementing represents a simple type.

Arguments

• Name of the type you want to implement GetSockOpt for.
• Socket layer, or a protocol level: could be raw sockets (lic::SOL_SOCKET), ip protocol (libc::IPPROTO_IP), tcp protocol (libc::IPPROTO_TCP), and more. Please refer to your system manual for more options. Will be passed as the second argument (level) to the getsockopt call.
• A flag to set. Some examples: libc::SO_REUSEADDR, libc::TCP_NODELAY, libc::SO_ORIGINAL_DST and others. Will be passed as the third argument (option_name) to the getsockopt call.
• Type of the value that you are going to get.
• Type that implements the Get trait for the type from the previous item (GetBool for bool, GetUsize for usize, etc.).