rssToBytes = 1
	case "illumos", "solaris":
		rssToBytes = uintptr(syscall.Getpagesize())
	default:
		panic("unsupported OS")
	}

	var rusage syscall.Rusage
	err := syscall.Getrusage(syscall.RUSAGE_SELF, &rusage)
	if err == nil {
		fmt.Fprintf(w, "# MaxRSS = %d\n", uintptr(rusage.Maxrss)*rssToBytes)
	}

	}

	var (
		status syscall.WaitStatus
		rusage syscall.Rusage
		pid1   int
		e      error
	)
	for {
		pid1, e = syscall.Wait4(p.Pid, &status, 0, &rusage)
		if e != syscall.EINTR {
			break
		}
	}
	if e != nil {
		return nil, NewSyscallError("wait", e)
	}
	p.pidDeactivate(statusDone)
	return &ProcessState{
		pid:    pid1,
		status: status,
		rusage: &rusage,
	}, nil
}

		return nil, syscall.EINVAL
	}
	defer p.handleTransientRelease()

	var (
		info   unix.SiginfoChild
		rusage syscall.Rusage
		e      syscall.Errno
	)
	for {
		_, _, e = syscall.Syscall6(syscall.SYS_WAITID, _P_PIDFD, handle, uintptr(unsafe.Pointer(&info)), syscall.WEXITED, uintptr(unsafe.Pointer(&rusage)), 0)
		if e != syscall.EINTR {
			break
		}
	}
	if e != 0 {
		return nil, NewSyscallError("waitid", e)
	}

	return time.Duration(n*100) * time.Nanosecond
}

func (p *ProcessState) userTime() time.Duration {
	return ftToDuration(&p.rusage.UserTime)
}

func (p *ProcessState) systemTime() time.Duration {
	return ftToDuration(&p.rusage.KernelTime)

}

// ProcessState stores information about a process, as reported by Wait.
type ProcessState struct {
	pid    int                // The process's id.
	status syscall.WaitStatus // System-dependent status info.
	rusage *syscall.Rusage
}

// Pid returns the process id of the exited process.
func (p *ProcessState) Pid() int {
	return p.pid
}

func (p *ProcessState) exited() bool {
	return p.status.Exited()
}

package pprof

import (
	"syscall"
	"time"
)

func init() {
	diffCPUTimeImpl = diffCPUTimeRUsage
}

func diffCPUTimeRUsage(f func()) (user, system time.Duration) {
	ok := true
	var before, after syscall.Rusage

	err := syscall.Getrusage(syscall.RUSAGE_SELF, &before)
	if err != nil {
		ok = false
	}

	f()

	err = syscall.Getrusage(syscall.RUSAGE_SELF, &after)
	if err != nil {
		ok = false
	}

// license that can be found in the LICENSE file.

//go:build !unix && !windows

package pprof

import (
	"io"
)

// Stub call for platforms that don't support rusage.
func addMaxRSS(w io.Writer) {

func (w WaitStatus) TrapCause() int     { return 0 }

// Rusage is a placeholder to allow compilation of the [os/exec] package
// because we need Go programs to be portable across platforms. WASI does
// not have a mechanism to to spawn processes so there is no reason for an
// application to take a dependency on this type.
type Rusage struct {
	Utime Timeval
	Stime Timeval
}

}

func (w WaitStatus) TrapCause() int { return -1 }

//sys	wait4(pid int, wstatus *_C_int, options int, rusage *Rusage) (wpid int, err error)

func Wait4(pid int, wstatus *WaitStatus, options int, rusage *Rusage) (wpid int, err error) {
	var status _C_int
	wpid, err = wait4(pid, &status, options, rusage)
	if wstatus != nil {
		*wstatus = WaitStatus(status)
	}
	return
}

//sys	wait4(pid Pid_t, status *_C_int, options int, rusage *Rusage) (wpid Pid_t, err error)

func Wait4(pid int, wstatus *WaitStatus, options int, rusage *Rusage) (wpid int, err error) {
	var status _C_int
	var r Pid_t
	err = ERESTART
	// AIX wait4 may return with ERESTART errno, while the processus is still
	// active.
	for err == ERESTART {
		r, err = wait4(Pid_t(pid), &status, options, rusage)
	}
	wpid = int(r)