text: // Copyright 2014 The Go Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  // +build aix darwin freebsd linux solaris
  
  package ipv6
  
  import (
  	"net"
  	"unsafe"
  
  	"golang.org/x/net/internal/socket"
  )
  
  var compatFreeBSD32 bool // 386 emulation on amd64
  
  func (so *sockOpt) setGroupReq(c *socket.Conn, ifi *net.Interface, grp net.IP) error {
  	var gr groupReq
  	if ifi != nil {
  		gr.Interface = uint32(ifi.Index)
  	}
  	gr.setGroup(grp)
  	var b []byte
  	if compatFreeBSD32 {
  		var d [sizeofGroupReq + 4]byte
  		s := (*[sizeofGroupReq]byte)(unsafe.Pointer(&gr))
  		copy(d[:4], s[:4])
  		copy(d[8:], s[4:])
  		b = d[:]
  	} else {
  		b = (*[sizeofGroupReq]byte)(unsafe.Pointer(&gr))[:sizeofGroupReq]
  	}
  	return so.Set(c, b)
  }
  
  func (so *sockOpt) setGroupSourceReq(c *socket.Conn, ifi *net.Interface, grp, src net.IP) error {
  	var gsr groupSourceReq
  	if ifi != nil {
  		gsr.Interface = uint32(ifi.Index)
  	}
  	gsr.setSourceGroup(grp, src)
  	var b []byte
  	if compatFreeBSD32 {
  		var d [sizeofGroupSourceReq + 4]byte
  		s := (*[sizeofGroupSourceReq]byte)(unsafe.Pointer(&gsr))
  		copy(d[:4], s[:4])
  		copy(d[8:], s[4:])
  		b = d[:]
  	} else {
  		b = (*[sizeofGroupSourceReq]byte)(unsafe.Pointer(&gsr))[:sizeofGroupSourceReq]
  	}
  	return so.Set(c, b)
  }
  