// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//

allowing a racing thread to read 1 as well.
</p>

<p>
Note that all these optimizations are permitted in C/C++ compilers:
a Go compiler sharing a back end with a C/C++ compiler must take care
to disable optimizations that are invalid for Go.
</p>

<p>
Note that the prohibition on introducing data races
does not apply if the compiler can prove that the races

    }
    return (byte) value;
  }

  /**
   * Compares the two specified {@code byte} values. The sign of the value returned is the same as
   * that of {@code ((Byte) a).compareTo(b)}.
   *
   * <p><b>Note:</b> this method behaves identically to {@link Byte#compare}.
   *
   * @param a the first {@code byte} to compare
   * @param b the second {@code byte} to compare

   * thus a motivated caller may be able to expose the reference to another thread that would then
   * call cancel() and be unable to cancel the delegate.
   * There are a number of ways to solve this, none of which are very pretty, and it is currently
   * believed to be a purely theoretical problem (since the other actions should supply sufficient
   * write-barriers).
   */

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//

## `Header`のパラメータの宣言

次に、`Path`や`Query`、`Cookie`と同じ構造を用いてヘッダーのパラメータを宣言します。

最初の値がデフォルト値で、追加の検証パラメータや注釈パラメータをすべて渡すことができます。

```Python hl_lines="9"
{!../../docs_src/header_params/tutorial001.py!}
```

/// note | "技術詳細"

`Header`は`Path`や`Query`、`Cookie`の「姉妹」クラスです。また、同じ共通の`Param`クラスを継承しています。

しかし、`fastapi`から`Query`や`Path`、`Header`などをインポートする場合、それらは実際には特殊なクラスを返す関数であることを覚えておいてください。

///

/// info | "情報"

    app,
    create_access_token,
    fake_users_db,
    get_password_hash,
    verify_password,
)

client = TestClient(app)


def get_access_token(username="johndoe", password="secret", scope=None):
    data = {"username": username, "password": password}
    if scope:
        data["scope"] = scope
    response = client.post("/token", data=data)
    content = response.json()

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//