---
title: "Block io mode?"
url: "https://maker.wiznet.io/forum/12036"
markdown_url: "https://maker.wiznet.io/forum/12036/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "youngjoonl"
created: "2016-11-23T08:14:51+09:00"
last_activity: "2017-05-04T08:39:27+09:00"
language: "en"
views: 786
replies: 2
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# Block io mode?

## Question

Asked by youngjoonl on 2016-11-23 in Ethernet Chips.

Socket API 설명을 보면 아래와 같은 설명이 나오는데…
W5500에는 “block io mode”, “non block io mode” 같은 설명이 없습니다.
이 용어의 의미가 무엇인지 좀 설명 부탁드립니다.

[color=#FF0000]Note:
It is valid only in TCP server or client mode. It can’t send data greater than socket buffer size.
In block io mode, It doesn’t return until data send is completed - socket buffer size is greater than data.
In non-block io mode, It return SOCK_BUSY immediatly when socket buffer is not enough. [/color]

## Replies

### Reply 1 by Edward, 2016-11-29

안녕하세요.

아래 링크 참조해주세요.

[kimilb412-2.blogspot.kr/2014/02/ … onous.html](http://kimilb412-2.blogspot.kr/2014/02/blocking-non-blocking-synchronous.html)

감사합니다.

### Reply 2 by youngjoonl, 2016-12-05

감사합니다.

잘이해되었습니다.

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Source: https://maker.wiznet.io/forum/12036