// The zero Value for LruList is an empty list ready to use.
type LruList[K comparable, V any] struct {
	root Entry[K, V] // sentinel list element, only &root, root.prev, and root.next are used
	len  int         // current list Length excluding (this) sentinel element
}

// Init initializes or clears list l.
func (l *LruList[K, V]) Init() *LruList[K, V] {
	l.root.next = &l.root
	l.root.prev = &l.root

        // Stop the thread by sending n = -1
        synchronized (w) {
            w.write(new byte[0], -1, out);
        }

        w.join(2000);
        assertFalse(w.isAlive(), "WriterThread should stop after -1 sentinel");
    }

    @Test
    @DisplayName("WriterThread surfaces SmbException via checkException")
    void writerThread_propagates_exception() throws Exception {
        // Arrange

C’est utile pour envoyer du texte préformaté, des lignes de log, ou des valeurs <dfn title="Une valeur utilisée pour indiquer une condition ou un état particulier">« sentinelle »</dfn> spéciales comme `[DONE]`.

{* ../../docs_src/server_sent_events/tutorial003_py310.py hl[17] *}

/// note | Remarque

    static final long TTL = Config.getLong("jcifs.smb1.smb.client.dfs.ttl", 300);
    static final boolean DISABLED = Config.getBoolean("jcifs.smb1.smb.client.dfs.disabled", false);

    /**
     * Sentinel cache entry indicating a negative cache result
     */
    protected static CacheEntry FALSE_ENTRY = new Dfs.CacheEntry(0L);

    /**
     * Cache of trusted domains for DFS resolution
     */

   * or empty headers if there were none that followed.
   *
   * If the response body was closed prematurely or failed with an error, this will be the sentinel
   * value [TRAILERS_RESPONSE_BODY_TRUNCATED]. In that case attempts to read the trailers should not
   * return the value but instead throw an exception.
   */
  private var trailers: Headers? = null

			return &buf
		},
	}

	direntNamePool = bpool.Pool[*[]byte]{
		New: func() *[]byte {
			buf := make([]byte, blockSize)
			return &buf
		},
	}
)

// unexpectedFileMode is a sentinel (and bogus) os.FileMode
// value used to represent a syscall.DT_UNKNOWN Dirent.Type.
const unexpectedFileMode os.FileMode = os.ModeNamedPipe | os.ModeSocket | os.ModeDevice

   *
   * @param method defaults to "GET" if [body] is null, and "POST" otherwise.
   */
  constructor(
    url: HttpUrl,
    headers: Headers = headersOf(),
    // '\u0000' is a sentinel value that'll choose based on what the body is:
    method: String = "\u0000",
    body: RequestBody? = null,
  ) : this(
    Builder()
      .url(url)
      .headers(headers)
      .method(
        when {

		// to set the Body to nil. But turns out too much code
		// depends on NewRequest returning a non-nil Body,
		// so we use a well-known ReadCloser variable instead
		// and have the http package also treat that sentinel
		// variable to mean explicitly zero.
		if req.GetBody != nil && req.ContentLength == 0 {
			req.Body = http.NoBody
			req.GetBody = func() (io.ReadCloser, error) { return http.NoBody, nil }
		}
	}

				time.Unix(0, 3).UTC(),
				time.Unix(0, 3).UTC(),
			},
			time.Unix(0, 3).UTC(),
			4,
		},
		{
			// 3. Tests common time obtained when elements have a mixture of
			// sentinel values and don't have read quorum on any of the values.
			[]time.Time{
				time.Unix(0, 3).UTC(),
				time.Unix(0, 3).UTC(),
				time.Unix(0, 2).UTC(),
				time.Unix(0, 1).UTC(),
				time.Unix(0, 3).UTC(),

   *
   * <p>Only runs of two or more hextets are considered. In case of a tie, the leftmost run wins. If
   * a qualifying run is found, its hextets are replaced by the sentinel value -1.
   *
   * @param hextets {@code int[]} mutable array of eight 16-bit hextets
   */
  private static void compressLongestRunOfZeroes(int[] hextets) {
    int bestRunStart = -1;
    int bestRunLength = -1;