// - Keep a ring buffer of the last N logical frames and use this to print
	//   the bottom frames once we reach the end of the stack. This works, but
	//   requires keeping a surprising amount of state on the stack, and we have
	//   to run the cgo symbolizer twice—once to count frames, and a second to
	//   print them—since we can't retain the strings it returns.
	//
	// Instead, we print the outer frames, and if we reach that limit, we clone

	var pcs [1]uintptr
	n := runtime.Callers(2, pcs[:])
	if n != 1 {
		panic(fmt.Sprintf("no caller of callerStartLine? n = %d", n))
	}

	frames := runtime.CallersFrames(pcs[:])
	frame, _ := frames.Next()

	inlined := frame.Func == nil // Func always set to nil for inlined frames
	if wantInlined != inlined {
		panic(fmt.Sprintf("caller %s inlined got %v want %v", frame.Function, inlined, wantInlined))
	}

	if fn != nil {
		frame := []driver.Frame{
			{
				Func: fn.Name,
				File: file,
				Line: line,
			},
		}
		return frame, nil
	}

	frames := f.dwarfSourceLine(addr)
	if frames != nil {
		return frames, nil
	}

	return nil, fmt.Errorf("no line information for PC=%#x", addr)
}

// dwarfSourceLine tries to get file/line information using DWARF.

	var frames []string
	if !w.encodingRelocHeader && w.p.syncFrames > 0 {
		pcs := make([]uintptr, w.p.syncFrames)
		n := runtime.Callers(2, pcs)
		frames = fmtFrames(pcs[:n]...)
	}

	// TODO(mdempsky): Save space by writing out stack frames as a
	// linked list so we can share common stack frames.
	w.rawUvarint(uint64(m))
	w.rawUvarint(uint64(len(frames)))
	for _, frame := range frames {

	uintptr_t* buf;
	uintptr_t  max;
};

// pprofCgoTraceback is passed to runtime.SetCgoTraceback.
// For testing purposes it pretends that all CPU hits in C code are in cpuHog.
// Issue #29034: At least 2 frames are required to verify all frames are captured
// since runtime/pprof ignores the runtime.goexit base frame if it exists.
void pprofCgoTraceback(void* parg) {
	struct cgoTracebackArg* arg = (struct cgoTracebackArg*)(parg);

	// the stack guard.
	//
	// Functions that need frames <= StackSmall can perform the stack check
	// using a single comparison directly between the stack guard and the SP
	// because we ensure that StackSmall bytes of stack space are available
	// beyond the stack guard.
	StackSmall = 128

	// Functions that need frames <= StackBig can assume that neither

	"github.com/google/pprof/internal/measurement"
	"github.com/google/pprof/profile"
)

// addLabelNodes adds pseudo stack frames "label:value" to each Sample with
// labels matching the supplied keys.
//
// rootKeys adds frames at the root of the callgraph (first key becomes new root).
// leafKeys adds frames at the leaf of the callgraph (last key becomes new leaf).
//
// Returns whether there were matches found for the label keys.

		}
		if keep {
			filtered.Events = append(filtered.Events, e)
		}
	}
	return
}

func stackFrames(data *format.Data, stackID int) (frames []string) {
	for {
		frame, ok := data.Frames[strconv.Itoa(stackID)]
		if !ok {
			return
		}
		frames = append(frames, frame.Name)
		stackID = frame.Parent
	}
}

func checkProcStartStop(t *testing.T, data format.Data) {
	procStarted := map[uint64]bool{}

	}
	ret := make([]uintptr, 20)
	return ret[:runtime.Callers(0, ret)] // line 27
}

func testCallers(t *testing.T, pcs []uintptr, pan bool) {
	m := make(map[string]int, len(pcs))
	frames := runtime.CallersFrames(pcs)
	for {
		frame, more := frames.Next()
		if frame.Function != "" {
			m[frame.Function] = frame.Line
		}
		if !more {
			break
		}
	}

	var seen []string
	for k := range m {
		seen = append(seen, k)

    /**
     * Invoked after a failure header has been printed, and before any stack frames have been printed.
     */
    void beforeFrames();

    /**
     * Invoked before a given stack frame is printed.
     */
    void beforeFrame(StackTraceElement element, StackTraceRelevance relevance);

    /**
     * Invoked after all stack frames of a failure have been printed.
     */
    void afterFrames();