}

var (
	mu     sync.Mutex
	inodes = map[File]inode{}
	locks  = map[inode]inodeLock{}
)

func lock(f File, lt lockType) (err error) {
	// POSIX locks apply per inode and process, and the lock for an inode is
	// released when *any* descriptor for that inode is closed. So we need to
	// synchronize access to each inode internally, and must serialize lock and
	// unlock calls that refer to the same inode through different descriptors.

			if errno == syscall.EINTR {
				continue
			}
			return names, dirents, infos, &PathError{Op: "readdir", Path: f.name, Err: errno}
		}
		if entptr == nil { // EOF
			break
		}
		// Darwin may return a zero inode when a directory entry has been
		// deleted but not yet removed from the directory. The man page for
		// getdirentries(2) states that programs are responsible for skipping
		// those entries:
		//

	f2 := mustOpen(t, f.Name())
	defer f2.Close()

	doUnlockTF := false
	switch runtime.GOOS {
	case "aix", "solaris":
		// When using POSIX locks (as on Solaris), we can't safely read-lock the
		// same inode through two different descriptors at the same time: when the
		// first descriptor is closed, the second descriptor would still be open but
		// silently unlocked. So a second RLock must block instead of proceeding.

func (fs *fileStat) IsDir() bool  { return fs.Mode().IsDir() }

// SameFile reports whether fi1 and fi2 describe the same file.
// For example, on Unix this means that the device and inode fields
// of the two underlying structures are identical; on other systems
// the decision may be based on the path names.
// SameFile only applies to results returned by this package's [Stat].
// It returns false in other cases.

// _EdgeC is the constraints on an edge in a graph, given the _Node type.
type _EdgeC[_Node any] interface {
	comparable
	Nodes() (a, b _Node)
}

// _New creates a new _Graph from a collection of Nodes.
func _New[_Node _NodeC[_Edge], _Edge _EdgeC[_Node]](nodes []_Node) *_Graph[_Node, _Edge] {
	return &_Graph[_Node, _Edge]{nodes: nodes}
}

// nodePath holds the path to a node during ShortestPath.

			break
		}
		// When building to wasip1, the host runtime might be running on Windows
		// or might expose a remote file system which does not have the concept
		// of inodes. Therefore, we cannot make the assumption that it is safe
		// to skip entries with zero inodes.
		if ino == 0 && runtime.GOOS != "wasip1" {
			continue
		}
		const namoff = uint64(unsafe.Offsetof(syscall.Dirent{}.Name))
		namlen, ok := direntNamlen(rec)

}

func (e posSpan) Pos() token.Pos {
	return e.pos
}

// inNode creates a posSpan for the given node.
// Invariant: node.Pos() <= pos < node.End() (node.End() is the position of the
// first byte after node within the source).
func inNode(node ast.Node, pos token.Pos) posSpan {
	start, end := node.Pos(), node.End()
	if debug {
		assert(start <= pos && pos < end)
	}
	return posSpan{start, pos, end}

}

type Utsname struct {
	Sysname  [257]byte
	Nodename [257]byte
	Release  [257]byte
	Version  [257]byte
	Machine  [257]byte
}

type Ustat_t struct {
	Tfree  int64
	Tinode uint64
	Fname  [6]int8
	Fpack  [6]int8
	_      [4]byte
}

const (
	AT_FDCWD            = 0xffd19553
	AT_SYMLINK_NOFOLLOW = 0x1000
	AT_SYMLINK_FOLLOW   = 0x2000
	AT_REMOVEDIR        = 0x1

// dump prints the contents of x.
// If x is the reflect.Value of a struct s, where &s
// implements Node, then &s should be passed for n -
// this permits printing of the unexported span and
// comments fields of the embedded isNode field by
// calling the Span() and Comment() instead of using
// reflection.
func (p *dumper) dump(x reflect.Value, n Node) {
	switch x.Kind() {
	case reflect.Interface:
		if x.IsNil() {
			p.printf("nil")

func argErrPos(call *ast.CallExpr) positioner { return inNode(call, call.Rparen) }

// startPos returns the start position of node n.
func startPos(n ast.Node) token.Pos { return n.Pos() }

// endPos returns the position of the first character immediately after node n.
func endPos(n ast.Node) token.Pos { return n.End() }