You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: wait_waitid.go
    path of file: ./repos/gccrs/libgo/go/os
    
    the code of the file until where you have to start completion: // Copyright 2016 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.

// We used to used this code for Darwin, but according to issue #19314
// waitid returns if the process is stopped, even when using WEXITED.

//go:build linux

package os

import (
	"runtime"
	"syscall"
	"unsafe"
)

const _P_PID = 1

// blockUntilWaitable attempts to block until a call to p.Wait will
// succeed immediately, and reports whether it has done so.
// It does not actually call p.Wait.
func (p *Process) blockUntilWaitable() (bool, error) {
	// The waitid system call expects a pointer to a si
    
func (p *Process) blockUntilWaitable() (bool, error) {
	// The waitid system call expects a pointer to a siginfo_t,
	// which is 128 bytes on all Linux systems.
	// On darwin/amd64, it requires 104 bytes.
	// We don't care about the values it returns.
	var siginfo [16]uint64
	psig := &siginfo[0]
	var r uintptr
	var e syscall.Errno
	for {
		r, _, e = syscall.Syscall6(syscall.SYS_WAITID, _P_PID, uintptr(p.Pid), uintptr(unsafe.Pointer(psig)), syscall.WEXITED|syscall.WNOWAIT, 0, 0)
		if e != syscall.EINTR {
			break
		}
	}
	runtime.KeepAlive(p)
	// Check r as well as e because syscall.Syscall6 currently
	// just returns errno, and the SIGCHLD signal handler may
	// change errno. See https://gcc.gnu.org/PR86331.
	if r != 0 && e != 0 {
		// waitid has been available since Linux 2.6.9, but
		// reportedly is not available in Ubuntu on Windows.
		// See issue 16610.
		if e == syscall.ENOSYS {
			return false, nil
		}
		return false, NewSyscallError("waitid", e)
	}
	return true, nil
}