// Copyright 2017 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 runtime_test import ( "fmt" "runtime" "strings" ) func ExampleFrames() { c := func() { // Ask runtime.Callers for up to 10 PCs, including runtime.Callers itself. pc := make([]uintptr, 10) n := runtime.Callers(0, pc) if n == 0 { // No PCs available. This can happen if the first argument to // runtime.Callers is large. // // Return now to avoid processing the zero Frame that would // otherwise be returned by frames.Next below. return } pc = pc[:n] // pass only valid pcs to runtime.CallersFrames frames := runtime.CallersFrames(pc) // Loop to get frames. // A fixed number of PCs can expand to an indefinite number of Frames. for { frame, more := frames.Next() // Process this frame. // // To keep this example's output stable // even if there are changes in the testing package, // stop unwinding when we leave package runtime. if !strings.Contains(frame.File, "runtime/") && !strings.Contains(frame.File, "/test/") { break } fmt.Printf("- more:%v | %s\n", more, frame.Function) // Check whether there are more frames to process after this one. if !more { break } } } b := func() { c() } a := func() { b() } a() // Output: // - more:true | runtime.Callers // - more:true | runtime_test.ExampleFrames..func1 // - more:true | runtime_test.ExampleFrames..func2 // - more:true | runtime_test.ExampleFrames..func3 // - more:true | runtime_test.ExampleFrames }