vendor/github.com/coreos/etcd/pkg/fileutil/sync_darwin.go

// Copyright 2016 The etcd Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// +build darwin

package fileutil

import (
	"os"
	"syscall"
)

// Fsync on HFS/OSX flushes the data on to the physical drive but the drive
// may not write it to the persistent media for quite sometime and it may be
// written in out-of-order sequence. Using F_FULLFSYNC ensures that the
// physical drive's buffer will also get flushed to the media.
func Fsync(f *os.File) error {
	_, _, errno := syscall.Syscall(syscall.SYS_FCNTL, f.Fd(), uintptr(syscall.F_FULLFSYNC), uintptr(0))
	if errno == 0 {
		return nil
	}
	return errno
}

// Fdatasync on darwin platform invokes fcntl(F_FULLFSYNC) for actual persistence
// on physical drive media.
func Fdatasync(f *os.File) error {
	return Fsync(f)
}