diff options
Diffstat (limited to 'src/time/sleep.go')
| -rw-r--r-- | src/time/sleep.go | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/src/time/sleep.go b/src/time/sleep.go index 90d8a18a68..4f45799414 100644 --- a/src/time/sleep.go +++ b/src/time/sleep.go @@ -101,7 +101,9 @@ func NewTimer(d Duration) *Timer { // It returns true if the timer had been active, false if the timer had // expired or been stopped. // -// Reset should be invoked only on stopped or expired timers with drained channels. +// For a Timer created with NewTimer, Reset should be invoked only on +// stopped or expired timers with drained channels. +// // If a program has already received a value from t.C, the timer is known // to have expired and the channel drained, so t.Reset can be used directly. // If a program has not yet received a value from t.C, however, @@ -120,6 +122,15 @@ func NewTimer(d Duration) *Timer { // is a race condition between draining the channel and the new timer expiring. // Reset should always be invoked on stopped or expired channels, as described above. // The return value exists to preserve compatibility with existing programs. +// +// For a Timer created with AfterFunc(d, f), Reset either reschedules +// when f will run, in which case Reset returns true, or schedules f +// to run again, in which case it returns false. +// When Reset returns false, Reset neither waits for the prior f to +// complete before returning nor does it guarantee that the subsequent +// goroutine running f does not run concurrently with the prior +// one. If the caller needs to know whether the prior execution of +// f is completed, it must coordinate with f explicitly. func (t *Timer) Reset(d Duration) bool { if t.r.f == nil { panic("time: Reset called on uninitialized Timer") |