// so this must be executed before CloseFunc.
	fd.pd.close()

	err := fd.SysFile.destroy(fd.Sysfd)

	fd.Sysfd = -1
	runtime_Semrelease(&fd.csema)
	return err
}

// Close closes the FD. The underlying file descriptor is closed by the
// destroy method when there are no remaining references.
func (fd *FD) Close() error {
	if !fd.fdmu.increfAndClose() {
		return errClosing(fd.isFile)
	}

		err := syscall.WSAIoctl(fd.Sysfd, syscall.SIO_UDP_CONNRESET, (*byte)(unsafe.Pointer(&flag)), size, nil, 0, &ret, nil, 0)
		if err != nil {
			return "wsaioctl", err
		}
	}
	fd.rop.mode = 'r'
	fd.wop.mode = 'w'
	fd.rop.fd = fd
	fd.wop.fd = fd
	fd.rop.runtimeCtx = fd.pd.runtimeCtx
	fd.wop.runtimeCtx = fd.pd.runtimeCtx
	return "", nil
}

func (fd *FD) destroy() error {

	SYS_FACCESSAT                = 489 // { int faccessat(int fd, char *path, int amode, \
	SYS_FCHMODAT                 = 490 // { int fchmodat(int fd, char *path, mode_t mode, \
	SYS_FCHOWNAT                 = 491 // { int fchownat(int fd, char *path, uid_t uid, \
	SYS_FEXECVE                  = 492 // { int fexecve(int fd, char **argv, \
	SYS_FUTIMESAT                = 494 // { int futimesat(int fd, char *path, \

	SYS_READV          = 120 // { ssize_t sys_readv(int fd, \
	SYS_WRITEV         = 121 // { ssize_t sys_writev(int fd, \
	SYS_KILL           = 122 // { int sys_kill(int pid, int signum); }
	SYS_FCHOWN         = 123 // { int sys_fchown(int fd, uid_t uid, gid_t gid); }
	SYS_FCHMOD         = 124 // { int sys_fchmod(int fd, mode_t mode); }
	SYS_SETREUID       = 126 // { int sys_setreuid(uid_t ruid, uid_t euid); }

		return nil, syscall.EINVAL
	}
	return newRawConn(c.fd), nil
}

// CloseRead shuts down the reading side of the Unix domain connection.
// Most callers should just use Close.
func (c *UnixConn) CloseRead() error {
	if !c.ok() {
		return syscall.EINVAL
	}
	if err := c.fd.closeRead(); err != nil {
		return &OpError{Op: "close", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
	}
	return nil
}

	SYS_MKFIFOAT       = 319 // { int sys_mkfifoat(int fd, const char *path, mode_t mode); }
	SYS_MKNODAT        = 320 // { int sys_mknodat(int fd, const char *path, mode_t mode, dev_t dev); }
	SYS_OPENAT         = 321 // { int sys_openat(int fd, const char *path, int flags, ... mode_t mode); }

	if e1 != 0 {
		err = errnoErr(e1)
	}
	return
}

// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT

func Fstat(fd int, stat *Stat_t) (err error) {
	_, _, e1 := Syscall(SYS_FSTAT, uintptr(fd), uintptr(unsafe.Pointer(stat)), 0)
	if e1 != 0 {
		err = errnoErr(e1)
	}
	return
}

// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT

		}
	case "udp":
		fd := ln.(*UDPConn).fd
		if err := checkDualStackAddrFamily(fd); err != nil {
			return err
		}
	case "udp4":
		fd := ln.(*UDPConn).fd
		if fd.family != syscall.AF_INET {
			return fmt.Errorf("%v got %v; want %v", fd.laddr, fd.family, syscall.AF_INET)
		}
	case "udp6":
		fd := ln.(*UDPConn).fd
		if fd.family != syscall.AF_INET6 {

	SYS_FCHOWNAT             = 464 // { int|sys||fchownat(int fd, const char *path, uid_t owner, gid_t group, int flag); }
	SYS_FEXECVE              = 465 // { int|sys||fexecve(int fd, char * const *argp, char * const *envp); }
	SYS_FSTATAT              = 466 // { int|sys||fstatat(int fd, const char *path, struct stat *buf, int flag); }

	SYS_FCHOWNAT             = 464 // { int|sys||fchownat(int fd, const char *path, uid_t owner, gid_t group, int flag); }
	SYS_FEXECVE              = 465 // { int|sys||fexecve(int fd, char * const *argp, char * const *envp); }
	SYS_FSTATAT              = 466 // { int|sys||fstatat(int fd, const char *path, struct stat *buf, int flag); }