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4524009ba6
The existing description of the function lacks usage examples, which makes it difficult to understand, so I added one. There is no open issue about this, since the implementation seems trivial. For #72795 Fixes #72796 Change-Id: I96b29f0b21d1c7fda04128239633c8a2fc36fef2 Reviewed-on: https://go-review.googlesource.com/c/go/+/649995 Reviewed-by: Carlos Amedee <carlos@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.com> Auto-Submit: Carlos Amedee <carlos@golang.org> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> (cherry picked from commit 4c75671871af56fa68076ee3741780e52726ec82) Reviewed-on: https://go-review.googlesource.com/c/go/+/656815 Reviewed-by: Cherry Mui <cherryyz@google.com>
96 lines
2.3 KiB
Go
96 lines
2.3 KiB
Go
// Copyright 2017 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package runtime_test
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import (
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"fmt"
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"os"
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"runtime"
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"strings"
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)
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func ExampleFrames() {
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c := func() {
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// Ask runtime.Callers for up to 10 PCs, including runtime.Callers itself.
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pc := make([]uintptr, 10)
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n := runtime.Callers(0, pc)
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if n == 0 {
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// No PCs available. This can happen if the first argument to
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// runtime.Callers is large.
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//
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// Return now to avoid processing the zero Frame that would
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// otherwise be returned by frames.Next below.
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return
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}
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pc = pc[:n] // pass only valid pcs to runtime.CallersFrames
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frames := runtime.CallersFrames(pc)
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// Loop to get frames.
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// A fixed number of PCs can expand to an indefinite number of Frames.
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for {
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frame, more := frames.Next()
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// Canonicalize function name and skip callers of this function
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// for predictable example output.
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// You probably don't need this in your own code.
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function := strings.ReplaceAll(frame.Function, "main.main", "runtime_test.ExampleFrames")
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fmt.Printf("- more:%v | %s\n", more, function)
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if function == "runtime_test.ExampleFrames" {
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break
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}
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// Check whether there are more frames to process after this one.
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if !more {
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break
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}
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}
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}
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b := func() { c() }
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a := func() { b() }
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a()
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// Output:
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// - more:true | runtime.Callers
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// - more:true | runtime_test.ExampleFrames.func1
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// - more:true | runtime_test.ExampleFrames.func2
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// - more:true | runtime_test.ExampleFrames.func3
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// - more:true | runtime_test.ExampleFrames
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}
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func ExampleAddCleanup() {
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tempFile, err := os.CreateTemp(os.TempDir(), "file.*")
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if err != nil {
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fmt.Println("failed to create temp file:", err)
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return
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}
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ch := make(chan struct{})
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// Attach a cleanup function to the file object.
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runtime.AddCleanup(&tempFile, func(fileName string) {
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if err := os.Remove(fileName); err == nil {
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fmt.Println("temp file has been removed")
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}
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ch <- struct{}{}
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}, tempFile.Name())
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if err := tempFile.Close(); err != nil {
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fmt.Println("failed to close temp file:", err)
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return
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}
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// Run the garbage collector to reclaim unreachable objects
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// and enqueue their cleanup functions.
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runtime.GC()
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// Wait until cleanup function is done.
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<-ch
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// Output:
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// temp file has been removed
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}
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