// 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 time

// A Ticker holds a channel that delivers “ticks” of a clock
// at intervals.
type Ticker struct {
	C <-chan Time // The channel on which the ticks are delivered.
	r runtimeTimer

// NewTicker returns a new Ticker containing a channel that will send
// the current time on the channel after each tick. The period of the
// ticks is specified by the duration argument. The ticker will adjust
// the time interval or drop ticks to make up for slow receivers.
// The duration d must be greater than zero; if not, NewTicker will
// panic. Stop the ticker to release associated resources.
func ( Duration) *Ticker {
	if  <= 0 {
		panic("non-positive interval for NewTicker")
	// Give the channel a 1-element time buffer.
	// If the client falls behind while reading, we drop ticks
	// on the floor until the client catches up.
	 := make(chan Time, 1)
	 := &Ticker{
		C: ,
		r: runtimeTimer{
			when:   when(),
			period: int64(),
			f:      sendTime,
			arg:    ,

// Stop turns off a ticker. After Stop, no more ticks will be sent.
// Stop does not close the channel, to prevent a concurrent goroutine
// reading from the channel from seeing an erroneous "tick".
func ( *Ticker) () {

// Reset stops a ticker and resets its period to the specified duration.
// The next tick will arrive after the new period elapses. The duration d
// must be greater than zero; if not, Reset will panic.
func ( *Ticker) ( Duration) {
	if  <= 0 {
		panic("non-positive interval for Ticker.Reset")
	if .r.f == nil {
		panic("time: Reset called on uninitialized Ticker")
	modTimer(&.r, when(), int64(), .r.f, .r.arg, .r.seq)

// Tick is a convenience wrapper for NewTicker providing access to the ticking
// channel only. While Tick is useful for clients that have no need to shut down
// the Ticker, be aware that without a way to shut it down the underlying
// Ticker cannot be recovered by the garbage collector; it "leaks".
// Unlike NewTicker, Tick will return nil if d <= 0.
func ( Duration) <-chan Time {
	if  <= 0 {
		return nil
	return NewTicker().C