net: document that DialIP can only be used with WriteMsgIP of Connection-less protocols #23230
Description
Please answer these questions before submitting your issue. Thanks!
What version of Go are you using (go version)?
go version go1.9.2 linux/amd64
Does this issue reproduce with the latest release?
yes
What operating system and processor architecture are you using (go env)?
go env
GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/ilyaigpetrov/go"
GORACE=""
GOROOT="/usr/lib/go-1.9"
GOTOOLDIR="/usr/lib/go-1.9/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build418566627=/tmp/go-build -gno-record-gcc-switches"
CXX="g++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"What did you do?
WriteMsgIP can't be used after DialIP to TCP
package main
import (
"net"
"fmt"
)
func main() {
loIP := net.IPv4(127,0,0,1)
// Accept TCP connections on localohst
listener, err := net.ListenTCP("tcp", &net.TCPAddr{ IP: loIP , Port: 0})
if err != nil {
panic(err)
}
go func(){
for {
_, err := listener.Accept()
if err != nil {
fmt.Println(err)
}
}
}()
// Dial localhost
ipconn, err := net.DialIP("ip:tcp", nil, &net.IPAddr{IP: loIP})
if err != nil {
panic(err)
}
_, _, err = ipconn.WriteMsgIP([]byte{11,22,33}, []byte{}, &net.IPAddr{ IP: loIP })
if err != nil {
panic(err)
}
fmt.Println("Heppy exit!")
}What did you expect to see?
It doesn't work. Error appears: write ip 127.0.0.1->127.0.0.1: use of WriteTo with pre-connected connection.
It seems DialIP can't be used with WriteMsgIP and I want this to be documented.
What did you see instead?
No documentation.