rancherOS/vendor/github.com/Sirupsen/logrus/terminal_windows.go

// Based on ssh/terminal:
// Copyright 2011 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 windows,!appengine

package logrus

import (
	"io"
	"os"
	"syscall"
	"unsafe"
)

var kernel32 = syscall.NewLazyDLL("kernel32.dll")

var (
	procGetConsoleMode = kernel32.NewProc("GetConsoleMode")
)

// IsTerminal returns true if stderr's file descriptor is a terminal.
func IsTerminal(f io.Writer) bool {
	switch v := f.(type) {
	case *os.File:
		var st uint32
		r, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, uintptr(v.Fd()), uintptr(unsafe.Pointer(&st)), 0)
		return r != 0 && e == 0
	default:
		return false
	}
}