blob: dcb8f7798e290581eab6858bbcb348966b0cd810 [file] [log] [blame]
// 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/") {
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
}