#### Blocking APIs

Blocking APIs are convenient because you get top-to-bottom procedural code without indirection. Network calls work like regular method calls: ask for data and it is returned. If the request fails, you get a stacktrace right where the call was made.

Blocking APIs may be inefficient because you hold a thread idle while waiting on the network. Threads are expensive because they have both a memory overhead and a context-switching overhead.

   * overkill for most Atomics because they are usually irregularly
   * scattered in memory and thus don't interfere much with each
   * other. But Atomic objects residing in arrays will tend to be
   * placed adjacent to each other, and so will most often share
   * cache lines (with a huge negative performance impact) without
   * this precaution.
   *
   * In part because Cells are relatively large, we avoid creating

                            * `security_scopes.scopes` will contain `["me"]` for the *path operation* `read_users_me`, because it is declared in the dependency `get_current_active_user`.
                            * `security_scopes.scopes` will contain `[]` (nothing) for the *path operation* `read_system_status`, because it didn't declare any `Security` with `scopes`, and its dependency, `get_current_user`, doesn't declare any `scopes` either.

/// tip

<img src="/img/tutorial/sub-applications/image02.png">

If you try interacting with any of the two user interfaces, they will work correctly, because the browser will be able to talk to each specific app or sub-app.

### Technical Details: `root_path` { #technical-details-root-path }

            "The SAM database on the Windows NT Server does not have a computer account for this workstation trust relationship.",
            "The logon request failed because the trust relationship between the primary domain and the trusted domain failed.",
            "The logon request failed because the trust relationship between this workstation and the primary domain failed.",

      int jellyBean =
          (int) Class.forName("android.os.Build$VERSION_CODES").getField("JELLY_BEAN").get(null);
      /*
       * I assume that this check can't fail because JELLY_BEAN will be present only if we're
       * running under Jelly Bean or higher. But it seems safest to check.
       */
      if (version < jellyBean) {
        return new ThrowingCreator();
      }

    int NT_STATUS_OBJECT_PATH_NOT_FOUND = 0xC000003a;
    /** The object path syntax is bad */
    int NT_STATUS_OBJECT_PATH_SYNTAX_BAD = 0xC000003b;
    /** The process cannot access the file because it is being used by another process */
    int NT_STATUS_SHARING_VIOLATION = 0xC0000043;
    /** The file is pending deletion */
    int NT_STATUS_DELETE_PENDING = 0xC0000056;

# The table name '$$ALL$$' means all tables are target.
# The table names and column names are treated as case insensitive.
#
# You don't need specify here about table classifications.
# Because table classifications are auto-deployed by relation information.
#
# Specification:
# map: {
#     [table-name or $$ALL$$] = map:{
#         ; [column-name (with hint)]=[classification-name]
#     }
# }
#

         * one, meaning this message cannot be batched.
         */
        return 0;
    }

    /*
     * We overload this method from ServerMessageBlock because
     * we want writeAndXWireFormat to write the parameterWords
     * and bytes. This is so we can write batched smbs because
     * all but the first smb of the chaain do not have a header
     * and therefore we do not want to writeHeaderWireFormat. We

So, during that time, the computer can go and do some other work, while "slow-file" 📝 finishes.

Then the computer / program 🤖 will come back every time it has a chance because it's waiting again, or whenever it 🤖 finished all the work it had at that point. And it 🤖 will see if any of the tasks it was waiting for have already finished, doing whatever it had to do.