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: sock_bsd.go
    path of file: ./repos/gccrs/libgo/go/net
    
    the code of the file until where you have to start completion: // 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.

//go:build darwin || dragonfly || freebsd || netbsd || openbsd

package net

impor
    
func maxListenerBacklog() int {
	var (
		n   uint32
		err error
	)
	switch runtime.GOOS {
	case "darwin", "ios":
		n, err = syscall.SysctlUint32("kern.ipc.somaxconn")
	case "freebsd":
		n, err = syscall.SysctlUint32("kern.ipc.soacceptqueue")
	case "netbsd":
		// NOTE: NetBSD has no somaxconn-like kernel state so far
	case "openbsd":
		n, err = syscall.SysctlUint32("kern.somaxconn")
	}
	if n == 0 || err != nil {
		return syscall.SOMAXCONN
	}
	// FreeBSD stores the backlog in a uint16, as does Linux.
	// Assume the other BSDs do too. Truncate number to avoid wrapping.
	// See issue 5030.
	if n > 1<<16-1 {
		n = 1<<16 - 1
	}
	return int(n)
}