"syscall"
)

// SetKeepAliveConfig configures keep-alive messages sent by the operating system.
func (c *TCPConn) SetKeepAliveConfig(config KeepAliveConfig) error {
	if !c.ok() {
		return syscall.EINVAL
	}

	if err := setKeepAlive(c.fd, config.Enable); err != nil {
		return &OpError{Op: "set", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
	}
	if unix.SupportTCPKeepAliveIdleIntvlCNT() {

	s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_STREAM|syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC, 0)
	if err == nil {
		syscall.Close(s)
	}
	wantSock := err != syscall.EPROTONOSUPPORT && err != syscall.EINVAL
	gotSock := unix.SupportSockNonblockCloexec()
	if wantSock != gotSock {
		t.Fatalf("SupportSockNonblockCloexec, got %t; want %t", gotSock, wantSock)
	}

	// Test that SupportAccept4 returns true if accept4 is available.

	if !c.ok() {
		return 0, syscall.EINVAL
	}
	n, err := c.fd.Read(b)
	if err != nil && err != io.EOF {
		err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
	}
	return n, err
}

// Write implements the Conn Write method.
func (c *conn) Write(b []byte) (int, error) {
	if !c.ok() {
		return 0, syscall.EINVAL
	}
	n, err := c.fd.Write(b)
	if err != nil {

	// being used is extremely unlikely.
	pid := math.MaxInt32
	if runtime.GOOS == "solaris" || runtime.GOOS == "illumos" {
		// Solaris/Illumos have a lower limit, above which wait returns
		// EINVAL (see waitid in usr/src/uts/common/os/exit.c in
		// illumos). This is configurable via sysconf(_SC_MAXPID), but
		// we'll just take the default.
		pid = 30000-1
	}

	p, err := FindProcess(pid)
	if err != nil {

	s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_STREAM|syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC, 0)
	if err == nil {
		syscall.Close(s)
		return true
	}
	if err != syscall.EPROTONOSUPPORT && err != syscall.EINVAL {
		// Something wrong with socket(), fall back to checking the kernel version.
		major, minor := KernelVersion()
		if runtime.GOOS == "illumos" {

// pointers to NUL-terminated byte arrays. If any string contains
// a NUL byte, it returns (nil, [EINVAL]).
func SlicePtrFromStrings(ss []string) ([]*byte, error) {
	n := 0
	for _, s := range ss {
		if bytealg.IndexByteString(s, 0) != -1 {
			return nil, EINVAL
		}
		n += len(s) + 1 // +1 for NUL
	}
	bb := make([]*byte, len(ss)+1)
	b := make([]byte, n)
	n = 0
	for i, s := range ss {

	//
	// Checking for statusDone here would not be a complete fix, as the PID
	// could still be waited on and reused prior to blockUntilWaitable.
	switch p.pidStatus() {
	case statusReleased:
		return nil, syscall.EINVAL
	}

	// If we can block until Wait4 will succeed immediately, do so.
	ready, err := p.blockUntilWaitable()
	if err != nil {
		return nil, err
	}
	if ready {

	if err != nil {
		t.Errorf("Faccessat: unexpected error: %v", err)
	}

	err = syscall.Faccessat(_AT_FDCWD, "file1", _R_OK, 2)
	if err != syscall.EINVAL {
		t.Errorf("Faccessat: unexpected error: %v, want EINVAL", err)
	}

	err = syscall.Faccessat(_AT_FDCWD, "file1", _R_OK, _AT_EACCESS)
	if err != nil {
		t.Errorf("Faccessat: unexpected error: %v", err)
	}

	if r1 == socket_error {
		if e1 != 0 {
			err = errnoErr(e1)
		} else {
			err = syscall.EINVAL
		}
	}
	return err
}

func WSARecvMsg(fd syscall.Handle, msg *WSAMsg, bytesReceived *uint32, overlapped *syscall.Overlapped, croutine *byte) error {
	err := loadWSASendRecvMsg()
	if err != nil {

		// pidfdFind. Return ECHILD for consistency with what the wait
		// syscall would return.
		return nil, NewSyscallError("wait", syscall.ECHILD)
	case statusReleased:
		return nil, syscall.EINVAL
	}
	defer p.handleTransientRelease()

	var (
		info   unix.SiginfoChild
		rusage syscall.Rusage
		e      syscall.Errno
	)
	for {