Comment 1:

I also feel want to have both socket and IP level option tweaking API 
sometimes. The problem to me is how designs nice and simple API 
because socket/IP level options contain tons of toggles; e.g., tons 
of member functions per ProtocolConn make me discourage...

Labels changed: added priority-later, removed priority-triage.

Comment 2:

Status changed to Accepted.

Comment 3:

This is what your program prints on my Windows:
-----------------
Input: 123
Input: read 123
456
Input: read 456
789
Input: read 789
panic: EOF
-----------------
Is that correct output or not? Either way, please, provide simpler program that does not
need any user input. And tell us what does new program prints when it runs, and what you
expect it to print instead. I do not know anything about multicast, so you have to be
specific. We could even use it to add new test to net package.
BTW, your program crashes on my linux computer:
panic: joinipv4group udp4 X.X.X.X: setsockopt: invalid argument
goroutine 1 [running]:
main.check(0x186344e0, 0x18634480)
        /root/t2/test.go:42 +0x46
main.main()
        /root/t2/test.go:17 +0xdd
goroutine 2 [syscall]:
created by runtime.main
        /root/hg/go/src/pkg/runtime/proc.c:221
goroutine 3 [syscall]:
syscall.Syscall6()
        /root/hg/go/src/pkg/syscall/asm_linux_386.s:0 +0x27
syscall.EpollWait(0x6, 0x18638008, 0xa, 0xa, 0xffffffff, ...)
        /root/hg/go/src/pkg/syscall/env_unix.go:0 +0x78
net.(*pollster).WaitFD(0x18638000, 0x18601540, 0x0, 0x0, 0x0, ...)
        /root/hg/go/src/pkg/net/fd_linux.go:146 +0x10c
net.(*pollServer).Run(0x18601540, 0x0)
        /root/hg/go/src/pkg/net/fd.go:236 +0xdf
created by net.newPollServer
        /root/hg/go/src/pkg/net/newpollserver.go:35 +0x308
exit status 2
Alex

Comment 4:

Issue #3826 has been merged into this issue.

Comment 5:

https://groups.google.com/d/topic/golang-dev/zbMTkiAq-Hw/discussion

Comment 6:

read, writemsg on IPConn
http://golang.org/cl/6426047/
go.net.ipv4 package proposal
http://golang.org/cl/6482044/

Comment 7:

Hi Mikio,
I've been following this set of changes closely, so I have an idea
what is going on, but I think it would be useful to send a quick email
to golang-dev explaining how all these CL's fit together and their
goal.

Comment 8:

Issue #3827 has been merged into this issue.

Comment 9:

This issue was closed by revision golang/net@d2e5a12.

Status changed to Fixed.

Comment 10:

Just curious about this check-in. Is it for the net/ipv4 package? The URL is not found.
keen to test it out.

Comment 11:

'go get code.google.com/p/go.net/ipv4'.

Comment 12:

Thanks. Works with tip.

Comment 13:

This issue was updated by revision golang/net@b073adc.

R=dave
CC=golang-dev
https://golang.org/cl/10125044

Comment 14:

404. That’s an error.
The requested URL /p/go/source/detail?r=b8dd04764dae was not found on this server.
That’s all we know.

Comment 15:

The right URL is https://code.google.com/p/go/source/detail?r=b8dd04764dae&repo=net.
I'll file a bug against Google Code.

Comment 16:

https://code.google.com/p/support/issues/detail?id=30811