bcmp(3)

bcmp3

Compare byte string

Usage

#include <strings.h>

int

bcmp(const void *b1, const void *b2, size_t len);

Library

Standard C Library (libc, -lc)

Overview

The bcmp() function compares byte string b1 against byte string b2, returning zero if they are identical, non-zero otherwise. Both strings are assumed to be len bytes long. Zero-length strings are always identical.

The strings may overlap.

Releases

87 releases since FreeBSD 2.0.5-RELEASE; the text changed 42 times.

  1. 2.0.5–3.3
  2. 3.4
  3. 3.5–3.5.1
  4. 4.0
  5. 4.1–4.3
  6. 4.4
  7. 4.5–4.11
  8. 5.0–5.1
  9. 5.2–6.3
  10. 6.4
  11. 7.0
  12. 7.1
  13. 7.2
  14. 7.3
  15. 7.4
  16. 8.0
  17. 8.1
  18. 8.2
  19. 8.3
  20. 8.4
  21. 9.0
  22. 9.1
  23. 9.2
  24. 9.3
  25. 10.0
  26. 10.1
  27. 10.2
  28. 10.3
  29. 10.4
  30. 11.0
  31. 11.1
  32. 11.2
  33. 11.3
  34. 11.4
  35. 12.0
  36. 12.1
  37. 12.2
  38. 12.3
  39. 12.4
  40. 13.0–13.2
  41. 13.3–14.5
  42. 15.0–15.1
  43. 16.0

History

A bcmp() function first appeared in 4.2BSD. Its prototype existed previously in ⟨string.h⟩ before it was moved to ⟨strings.h⟩ for IEEE Std 1003.1-2001 (“POSIX.1”) compliance.

IEEE Std 1003.1-2008 (“POSIX.1”) removes the specification of bcmp() and it is marked as LEGACY in IEEE Std 1003.1-2004 (“POSIX.1”). For portability with other systems new programs should use memcmp(3).

From base 16.0-CURRENT-20261027-61c70dc16a79 in FreeBSD 16.0-CURRENT (2026-10-27). Parsed by carta from the page's mdoc source.