mirror of
https://github.com/golang/go
synced 2024-09-06 00:19:45 +00:00
58 lines
975 B
Go
58 lines
975 B
Go
![]() |
// run
|
||
|
|
||
|
// Copyright 2018 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 main
|
||
|
|
||
|
import (
|
||
|
"fmt"
|
||
|
"runtime"
|
||
|
)
|
||
|
|
||
|
type HeapObj [8]int64
|
||
|
|
||
|
type StkObj struct {
|
||
|
h *HeapObj
|
||
|
}
|
||
|
|
||
|
var n int
|
||
|
var c int = -1
|
||
|
|
||
|
func gc() {
|
||
|
// encourage heap object to be collected, and have its finalizer run.
|
||
|
runtime.GC()
|
||
|
runtime.GC()
|
||
|
runtime.GC()
|
||
|
n++
|
||
|
}
|
||
|
|
||
|
func main() {
|
||
|
f()
|
||
|
gc() // prior to stack objects, heap object is not collected until here
|
||
|
if c < 0 {
|
||
|
panic("heap object never collected")
|
||
|
}
|
||
|
if c != 1 {
|
||
|
panic(fmt.Sprintf("expected collection at phase 1, got phase %d", c))
|
||
|
}
|
||
|
}
|
||
|
|
||
|
func f() {
|
||
|
var s StkObj
|
||
|
s.h = new(HeapObj)
|
||
|
runtime.SetFinalizer(s.h, func(h *HeapObj) {
|
||
|
// Remember at what phase the heap object was collected.
|
||
|
c = n
|
||
|
})
|
||
|
g(&s)
|
||
|
gc()
|
||
|
}
|
||
|
|
||
|
func g(s *StkObj) {
|
||
|
gc() // heap object is still live here
|
||
|
runtime.KeepAlive(s)
|
||
|
gc() // heap object should be collected here
|
||
|
}
|