From 8f37544a79ae7c694de6b3b7208ee06bdc86c308 Mon Sep 17 00:00:00 2001 From: Zahari Dichev Date: Wed, 21 Oct 2020 14:32:50 +0300 Subject: io: explain how to determine number of bytes read in AsyncRead (#3011) Fixes: #2999 --- tokio/src/io/async_read.rs | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/tokio/src/io/async_read.rs b/tokio/src/io/async_read.rs index 1ca045bd..d075443a 100644 --- a/tokio/src/io/async_read.rs +++ b/tokio/src/io/async_read.rs @@ -16,8 +16,9 @@ use std::task::{Context, Poll}; /// the following: /// /// * `Poll::Ready(Ok(()))` means that data was immediately read and placed into -/// the output buffer. If no data was read (`buf.filled().is_empty()`) it -/// implies that EOF has been reached. +/// the output buffer. The amount of data read can be determined by the +/// increase in the length of the slice returned by `ReadBuf::filled`. If the +/// difference is 0, EOF has been reached. /// /// * `Poll::Pending` means that no data was read into the buffer /// provided. The I/O object is not currently readable but may become readable -- cgit v1.2.3