net: connecting to 0.0.0.0 fails on windows

[alexbrainman]

What steps will reproduce the problem?

run this program on windows

package main

import (
    "log"
    "net"
)

func dial() error {
    l, err := net.Listen("tcp", ":0")
    if err != nil {
        return err
    }

    go func() {
        c, err := l.Accept()
        if err != nil {
            return
        }
        c.Close()
    }()

    c, err := net.Dial("tcp", l.Addr().String())
    if err != nil {
        return err
    }
    c.Close()
    return nil
}

func main() {
    err := dial()
    if err != nil {
        log.Fatal(err)
    }
}


What is the expected output?

Should output noting.

What do you see instead?

2013/08/30 16:43:22 dial tcp 0.0.0.0:1406: ConnectEx tcp: The format of the specified
network name is invalid.

Please use labels and text to provide additional information.

The problem seems to be that l.Addr().String() returns '0.0.0.0', but connecting to that
address is not allowed on windows. From
http://msdn.microsoft.com/en-us/library/aa923167.aspx

" ... If the address member of the structure specified by the name parameter is
all zeroes, connect will return the error WSAEADDRNOTAVAIL. ..."

[alexbrainman]

Comment 1:

mikio,
Can we, please, decide what to do here? Thank you.
Alex

[mikioh]

Comment 2:

I think accepting an wildcard address "0.0.0.0" or "::" might be better but let's
postpone until Go 1.3 because I'm not sure what happens in the case of raw socket on
Windows.

[rsc]

Comment 3:

Labels changed: added go1.3maybe.

[rsc]

Comment 4:

Labels changed: added release-none, removed go1.3maybe.

[rsc]

Comment 5:

Labels changed: added repo-main.

[bradfitz]

Let's at least remove that example from the docs on the Dial func. It's weird to connect to 0.0.0.0.

[taylorchu]

The doc says: If the host is empty, as in ":80", the local system is assumed. I interpret that local system as localhost (127.0.0.1) instead of 0.0.0.0. It will be nice if this is clarified in the doc.

[mikioh]

#10624 will update the documentation; It will probably have a section about "Network and host/address arguments."

[gopherbot]

CL https://golang.org/cl/31950 mentions this issue.

[rsc]

I think we should fix this. We advertise that Dial(":80") connects to the local system's port 80. It should do that on Windows too. I'll send a CL with a test and a fix; criticisms welcome.

[gopherbot]

CL https://golang.org/cl/32101 mentions this issue.