Document that UdpSocket::recv and recv_from do not read from the buffer

[dtolnay]

fn recv(&self, buf: &mut [u8]) -> Result<usize>;
fn recv_from(&self, buf: &mut [u8]) -> Result<(usize, SocketAddr)>;

It is important for these to document that they only write to the buffer, not read from it, because that means it is safe to pass an uninitialized buffer. It would be wasteful to construct a buffer, initialize it to contain all 0 bytes, and pass it to UdpSocket.

[frehberg]

And add to the docs, if recv returns with Ok(N), the following code must not iterate over complete array, but iterate over a slice of the array buf[0,..,N-1].

[frehberg]

can be closed?

[dtolnay]

I don't think so. The docs in mio still need some work.

mio/src/net/udp.rs

Lines 79 to 81 in 5b9d20c

	/// Receives data from the socket. On success, returns the number of bytes
	/// read and the address from whence the data came.
	pub fn recv_from(&self, buf: &mut [u8]) -> io::Result<(usize, SocketAddr)> {

[frehberg]

Finally the patch has been rebased, and could be merged

[carllerche]

The original PR got messed up somehow. I moved the commit to #775.

[carllerche]

Thanks. This has been merged (f6f293f).