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: sysvshm_unix.go
    path of file: ./repos/plumber/vendor/golang.org/x/sys/unix
    
    the code of the file until where you have to start completion: // Copyright 2021 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.

//go:build (darwin && !ios) || linux

package unix

import "unsafe"

// SysvShmAttach attaches the Sysv shared memory segment associated with the
// shared memory identifier id.
func SysvShmAttach(id int, addr uintptr, flag int) ([]byte, error) {
	addr, errno := shmat(id, addr, flag)
	if errno != nil {
	
    
func SysvShmAttach(id int, addr uintptr, flag int) ([]byte, error) {
	addr, errno := shmat(id, addr, flag)
	if errno != nil {
		return nil, errno
	}

	// Retrieve the size of the shared memory to enable slice creation
	var info SysvShmDesc

	_, err := SysvShmCtl(id, IPC_STAT, &info)
	if err != nil {
		// release the shared memory if we can't find the size

		// ignoring error from shmdt as there's nothing sensible to return here
		shmdt(addr)
		return nil, err
	}

	// Use unsafe to convert addr into a []byte.
	b := unsafe.Slice((*byte)(unsafe.Pointer(addr)), int(info.Segsz))
	return b, nil
}