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// 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 os
import (
"runtime"
"syscall"
)
// Options for Wait.
const (
WNOHANG = syscall.WNOHANG // Don't wait if no process has exited.
WSTOPPED = syscall.WSTOPPED // If set, status of stopped subprocesses is also reported.
WUNTRACED = syscall.WUNTRACED // Usually an alias for WSTOPPED.
WRUSAGE = 1 << 20 // Record resource usage.
)
// WRUSAGE must not be too high a bit, to avoid clashing with Linux's
// WCLONE, WALL, and WNOTHREAD flags, which sit in the top few bits of
// the options
// Wait waits for the Process to exit or stop, and then returns a
// Waitmsg describing its status and an Error, if any. The options
// (WNOHANG etc.) affect the behavior of the Wait call.
func (p *Process) Wait(options int) (w *Waitmsg, err Error) {
if p.Pid == -1 {
return nil, EINVAL
}
var status syscall.WaitStatus
var rusage *syscall.Rusage
if options&WRUSAGE != 0 {
rusage = new(syscall.Rusage)
options ^= WRUSAGE
}
pid1, e := syscall.Wait4(p.Pid, &status, options, rusage)
if e != 0 {
return nil, NewSyscallError("wait", e)
}
w = new(Waitmsg)
w.Pid = pid1
w.WaitStatus = status
w.Rusage = rusage
return w, nil
}
// Release releases any resources associated with the Process.
func (p *Process) Release() Error {
// NOOP for unix.
p.Pid = -1
// no need for a finalizer anymore
runtime.SetFinalizer(p, nil)
return nil
}
// FindProcess looks for a running process by its pid.
// The Process it returns can be used to obtain information
// about the underlying operating system process.
func FindProcess(pid int) (p *Process, err Error) {
// NOOP for unix.
return newProcess(pid, 0), nil
}