|  | // Copyright 2009 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. | 
|  |  | 
|  | package net | 
|  |  | 
|  | import ( | 
|  | "os" | 
|  | "runtime" | 
|  | "syscall" | 
|  | "time" | 
|  | "unsafe" | 
|  | ) | 
|  |  | 
|  | func setKeepAlivePeriod(fd *netFD, d time.Duration) error { | 
|  | // The kernel expects milliseconds so round to next highest | 
|  | // millisecond. | 
|  | d += (time.Millisecond - time.Nanosecond) | 
|  | msecs := uint32(d / time.Millisecond) | 
|  | ka := syscall.TCPKeepalive{ | 
|  | OnOff:    1, | 
|  | Time:     msecs, | 
|  | Interval: msecs, | 
|  | } | 
|  | ret := uint32(0) | 
|  | size := uint32(unsafe.Sizeof(ka)) | 
|  | err := fd.pfd.WSAIoctl(syscall.SIO_KEEPALIVE_VALS, (*byte)(unsafe.Pointer(&ka)), size, nil, 0, &ret, nil, 0) | 
|  | runtime.KeepAlive(fd) | 
|  | return os.NewSyscallError("wsaioctl", err) | 
|  | } |