Doc test.

Author: kinetiknz

src/sys/socket/mod.rs

@@ -202,7 +202,12 @@ type align_of_cmsg_data = size_t;
 ///
 /// To make room for multiple messages, nest the type parameter with
 /// tuples, e.g.
-/// `let cmsg: CmsgSpace<([RawFd; 3], CmsgSpace<[RawFd; 2]>)> = CmsgSpace::new();`
+///
+/// ```
+/// use std::os::unix::io::RawFd;
+/// use nix::sys::socket::CmsgSpace;
+/// let cmsg: CmsgSpace<([RawFd; 3], CmsgSpace<[RawFd; 2]>)> = CmsgSpace::new();
+/// ```
 #[repr(C)]
 pub struct CmsgSpace<T> {
     _hdr: cmsghdr,