/contrib/ntp/include/isc/magic.h

https://bitbucket.org/freebsd/freebsd-head/ · C++ Header · 40 lines · 9 code · 7 blank · 24 comment · 3 complexity · 5d4e3b51b4e666c9c62b623871d7a464 MD5 · raw file

  1. /*
  2. * Copyright (C) 1999-2001 Internet Software Consortium.
  3. *
  4. * Permission to use, copy, modify, and distribute this software for any
  5. * purpose with or without fee is hereby granted, provided that the above
  6. * copyright notice and this permission notice appear in all copies.
  7. *
  8. * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
  9. * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
  10. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
  11. * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
  12. * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
  13. * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
  14. * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
  15. * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16. */
  17. /* $Id: magic.h,v 1.11 2001/01/09 21:57:10 bwelling Exp $ */
  18. #ifndef ISC_MAGIC_H
  19. #define ISC_MAGIC_H 1
  20. typedef struct {
  21. unsigned int magic;
  22. } isc__magic_t;
  23. /*
  24. * To use this macro the magic number MUST be the first thing in the
  25. * structure, and MUST be of type "unsigned int".
  26. *
  27. * The intent of this is to allow magic numbers to be checked even though
  28. * the object is otherwise opaque.
  29. */
  30. #define ISC_MAGIC_VALID(a,b) (((a) != NULL) && \
  31. (((const isc__magic_t *)(a))->magic == (b)))
  32. #define ISC_MAGIC(a, b, c, d) ((a) << 24 | (b) << 16 | (c) << 8 | (d))
  33. #endif /* ISC_MAGIC_H */