devclass(9)

devclass9

Object representing a class of devices

Usage

typedef struct devclass *devclass_t;

Overview

The devclass object has two main functions in the system. The first is to manage the allocation of unit numbers for device instances and the second is to hold the list of device drivers for a particular bus type. Each devclass has a name and there cannot be two devclasses with the same name. This ensures that unique unit numbers are allocated to device instances. All instances with the same name are treated as being the same.

When no specific unit number is needed, DEVICE_UNIT_ANY is used.

Releases

77 releases since FreeBSD 3.0-RELEASE; the text changed 41 times.

  1. 3.0–3.1
  2. 3.2
  3. 3.3–3.5.1
  4. 4.0–4.2
  5. 4.3
  6. 4.4–4.11
  7. 5.0–5.1
  8. 5.2–5.5
  9. 6.0–6.3
  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. 15.0–16.0

Authors

This manual page was written by Doug Rabson.

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