// Copyright 2009 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

// Breakpoint() executes a breakpoint trap.
func Breakpoint()

// LockOSThread wires the calling goroutine to its current operating system thread.
// Until the calling goroutine exits or calls UnlockOSThread, it will always
// execute in that thread, and no other goroutine can.
// LockOSThread cannot be used during init functions.
func LockOSThread()

// UnlockOSThread unwires the calling goroutine from its fixed operating system thread.
// If the calling goroutine has not called LockOSThread, UnlockOSThread is a no-op.
func UnlockOSThread()

// GOMAXPROCS sets the maximum number of CPUs that can be executing
// simultaneously and returns the previous setting.  If n < 1, it does not
// change the current setting.
// This call will go away when the scheduler improves.
func GOMAXPROCS(n int) int

// Cgocalls returns the number of cgo calls made by the current process.
func Cgocalls() int64

// Goroutines returns the number of goroutines that currently exist.
func Goroutines() int32

// Alloc allocates a block of the given size.
// FOR TESTING AND DEBUGGING ONLY.
func Alloc(uintptr) *byte

// Free frees the block starting at the given pointer.
// FOR TESTING AND DEBUGGING ONLY.
func Free(*byte)

// Lookup returns the base and size of the block containing the given pointer.
// FOR TESTING AND DEBUGGING ONLY.
func Lookup(*byte) (*byte, uintptr)

// MemProfileRate controls the fraction of memory allocations
// that are recorded and reported in the memory profile.
// The profiler aims to sample an average of
// one allocation per MemProfileRate bytes allocated.
//
// To include every allocated block in the profile, set MemProfileRate to 1.
// To turn off profiling entirely, set MemProfileRate to 0.
//
// The tools that process the memory profiles assume that the
// profile rate is constant across the lifetime of the program
// and equal to the current value.  Programs that change the
// memory profiling rate should do so just once, as early as
// possible in the execution of the program (for example,
// at the beginning of main).
var MemProfileRate int = 512 * 1024

// A MemProfileRecord describes the live objects allocated
// by a particular call sequence (stack trace).
type MemProfileRecord struct {
	AllocBytes, FreeBytes     int64       // number of bytes allocated, freed
	AllocObjects, FreeObjects int64       // number of objects allocated, freed
	Stack0                    [32]uintptr // stack trace for this record; ends at first 0 entry
}

// InUseBytes returns the number of bytes in use (AllocBytes - FreeBytes).
func (r *MemProfileRecord) InUseBytes() int64 { return r.AllocBytes - r.FreeBytes }

// InUseObjects returns the number of objects in use (AllocObjects - FreeObjects).
func (r *MemProfileRecord) InUseObjects() int64 {
	return r.AllocObjects - r.FreeObjects
}

// Stack returns the stack trace associated with the record,
// a prefix of r.Stack0.
func (r *MemProfileRecord) Stack() []uintptr {
	for i, v := range r.Stack0 {
		if v == 0 {
			return r.Stack0[0:i]
		}
	}
	return r.Stack0[0:]
}

// MemProfile returns n, the number of records in the current memory profile.
// If len(p) >= n, MemProfile copies the profile into p and returns n, true.
// If len(p) < n, MemProfile does not change p and returns n, false.
//
// If inuseZero is true, the profile includes allocation records
// where r.AllocBytes > 0 but r.AllocBytes == r.FreeBytes.
// These are sites where memory was allocated, but it has all
// been released back to the runtime.
// Most clients should use the runtime/pprof package or
// the testing package's -test.memprofile flag instead
// of calling MemProfile directly.
func MemProfile(p []MemProfileRecord, inuseZero bool) (n int, ok bool)

// CPUProfile returns the next chunk of binary CPU profiling stack trace data,
// blocking until data is available.  If profiling is turned off and all the profile
// data accumulated while it was on has been returned, CPUProfile returns nil.
// The caller must save the returned data before calling CPUProfile again.
// Most clients should use the runtime/pprof package or
// the testing package's -test.cpuprofile flag instead of calling
// CPUProfile directly.
func CPUProfile() []byte

// SetCPUProfileRate sets the CPU profiling rate to hz samples per second.
// If hz <= 0, SetCPUProfileRate turns off profiling.
// If the profiler is on, the rate cannot be changed without first turning it off.
// Most clients should use the runtime/pprof package or
// the testing package's -test.cpuprofile flag instead of calling
// SetCPUProfileRate directly.
func SetCPUProfileRate(hz int)