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Diffstat (limited to '')
-rw-r--r-- | lib/isc/include/isc/magic.h | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/lib/isc/include/isc/magic.h b/lib/isc/include/isc/magic.h new file mode 100644 index 0000000..5e2f184 --- /dev/null +++ b/lib/isc/include/isc/magic.h @@ -0,0 +1,31 @@ +/* + * Copyright (C) Internet Systems Consortium, Inc. ("ISC") + * + * SPDX-License-Identifier: MPL-2.0 + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, you can obtain one at https://mozilla.org/MPL/2.0/. + * + * See the COPYRIGHT file distributed with this work for additional + * information regarding copyright ownership. + */ + +#pragma once + +/*! \file isc/magic.h */ + +typedef struct { + unsigned int magic; +} isc__magic_t; + +/*% + * To use this macro the magic number MUST be the first thing in the + * structure, and MUST be of type "unsigned int". + * The intent of this is to allow magic numbers to be checked even though + * the object is otherwise opaque. + */ +#define ISC_MAGIC_VALID(a, b) \ + ((a) != NULL && ((const isc__magic_t *)(a))->magic == (b)) + +#define ISC_MAGIC(a, b, c, d) ((a) << 24 | (b) << 16 | (c) << 8 | (d)) |