i := 0
	for n != 0 {
		// amd64/v1,amd64/v2:"BSFL",-"BTSQ"
		// amd64/v3:"TZCNTL"
		i += bits.TrailingZeros32(n)
		n &= n - 1
	}
	return i
}

func IterateBits16(n uint16) int {
	i := 0
	for n != 0 {
		// amd64/v1,amd64/v2:"BSFL",-"BTSL"
		// amd64/v3:"TZCNTL"
		// arm64:"RBITW","CLZW",-"ORR"
		i += bits.TrailingZeros16(n)
		n &= n - 1
	}
	return i
}

// used by internal/poll
//go:linkname fdopendir

// used by internal/syscall/unix
//go:linkname unlinkat
//go:linkname openat
//go:linkname fstatat

// used by cmd/link
//go:linkname msync

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build unix

package runtime

import _ "unsafe"

// used in internal/syscall/unix

// Support for SOCK_* flags as part of the type parameter was added to Oracle
// Solaris in the 11.4 release. Thus, on releases prior to 11.4, we fall back
// to the combination of socket(3c) and fcntl(2).

package net

import (
	"internal/poll"
	"internal/syscall/unix"
	"os"
	"syscall"
)

// Wrapper around the socket system call that marks the returned file

// The accept4(3c) function was added to Oracle Solaris in the Solaris 11.4.0
// release. Thus, on releases prior to 11.4, we fall back to the combination
// of accept(3c) and fcntl(2).

package poll

import (
	"internal/syscall/unix"
	"syscall"
)

// Wrapper around the accept system call that marks the returned file
// descriptor as nonblocking and close-on-exec.

// Not used on Darwin, but must be defined.
func exitThread(wait *atomic.Uint32) {
	throw("exitThread")
}

//go:nosplit
func setNonblock(fd int32) {
	flags, _ := fcntl(fd, _F_GETFL, 0)
	if flags != -1 {
		fcntl(fd, _F_SETFL, flags|_O_NONBLOCK)
	}
}

func issetugid() int32 {
	return libcCall(unsafe.Pointer(abi.FuncPCABI0(issetugid_trampoline)), nil)
}
func issetugid_trampoline()

GOARCH=386 go tool cgo -cdefs defs_freebsd.go >defs_freebsd_386.h
GOARCH=arm go tool cgo -cdefs defs_freebsd.go >defs_freebsd_arm.h
*/

package runtime

/*
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/time.h>
#include <signal.h>
#include <errno.h>
#include <sys/event.h>
#include <sys/mman.h>
#include <sys/ucontext.h>
#include <sys/umtx.h>
#include <sys/_umtx.h>
#include <sys/rtprio.h>

#define __DARWIN_UNIX03 0
#include <mach/mach_time.h>
#include <sys/types.h>
#include <sys/time.h>
#include <errno.h>
#include <signal.h>
#include <sys/event.h>
#include <sys/mman.h>
#include <pthread.h>
#include <fcntl.h>
*/
import "C"

const (
	EINTR     = C.EINTR
	EFAULT    = C.EFAULT
	EAGAIN    = C.EAGAIN
	ETIMEDOUT = C.ETIMEDOUT

	PROT_NONE  = C.PROT_NONE
	PROT_READ  = C.PROT_READ
	PROT_WRITE = C.PROT_WRITE

		r0, err := unix.Fcntl(fd, syscall.F_DUPFD_CLOEXEC, 0)
		if err == nil {
			return r0, "", nil
		}
		switch err {
		case syscall.EINVAL, syscall.ENOSYS:
			// Old kernel, or js/wasm (which returns
			// ENOSYS). Fall back to the portable way from
			// now on.
			dupCloexecUnsupported.Store(true)
		default:
			return -1, "fcntl", err
		}
	}
	return dupCloseOnExecOld(fd)
}

#include <netinet/ip_mroute.h>
#include <sys/protosw.h>
#include <sys/stropts.h>
#include <sys/mman.h>
#include <sys/poll.h>
#include <sys/select.h>
#include <sys/termio.h>
#include <termios.h>
#include <fcntl.h>

#define AF_LOCAL AF_UNIX
'

includes_Darwin='
#define _DARWIN_C_SOURCE
#define KERNEL 1
#define _DARWIN_USE_64_BIT_INODE
#define __APPLE_USE_RFC_3542
#include <stdint.h>
#include <sys/attr.h>