Function sockname 

unsafe fn sockname<F>(f: F) -> Result<SocketAddr>
where
    F: FnOnce(*mut sockaddr, *mut socklen_t) -> c_int,

Wraps a call to a platform function that returns a socket address.

Safety

• if f returns a success (i.e. cvt returns Ok when called on the return value), the buffer provided to f must have been initialized with a valid C socket address, the length of which must be written to the second argument.