syscall.Write returns broken pipe while tcp connection establish

Question

Background

• To learn network programming, I tried to write raw socket by Golang, did not use net module.

Procedure

• 1. Server binds socket(syscall.Bind) and listens(syscall.Listen).
• 2. client tries to connect(syscall.Connect) and server accepts(syscall.Accepts)
• 3. server responses "Hello" to socket by syscall.Write.
• 4. client reads socket by syscall.Read

then, code is here ->

https://gist.github.com/ryfjwr/21e01fb5e133861b41e981e14ced8672

Problem

• above Procedure, while executing step 3, server exists because of broken pipe.

• at first, run server

  $ go run tcp-server.go

• then, run client

  $ go run tcp-client.go

• then gets broken pipe error.

  $ go run tcp-server.go

  Write Error broken pipe exit

Question

• Why Broken pipe occurs? Any other reserch thing?
  • I investigated same situation, When you have written to a connection that has already been closed by the peer., but, I triggerd sleep, before client exits.
  • source: c++ - Socket: send() function returned 'Broken Pipe' error - Stack Overflow