sigmask(2)

sigmask2

Manipulate current signal mask

Part of sigsetmask(2).

Usage

#include <signal.h>

int

sigsetmask(int mask);

int

sigblock(int mask);

int

sigmask(int signum);

Library

Standard C Library (libc, -lc)

Overview

This interface is made obsolete by: sigprocmask(2).

The sigsetmask() function sets the current signal mask to the specified mask. Signals are blocked from delivery if the corresponding bit in mask is a 1. The sigblock() function adds the signals in the specified mask to the current signal mask, rather than overwriting it as sigsetmask() does. The macro sigmask() is provided to construct the mask for a given signum.

The system quietly disallows SIGKILL or SIGSTOP to be blocked.

Return values

The sigblock() and sigsetmask() functions return the previous set of masked signals.

Releases

56 releases since FreeBSD 5.0-RELEASE; the text changed 34 times.

  1. 5.0
  2. 5.1–6.3
  3. 6.4
  4. 7.0
  5. 7.1
  6. 7.2
  7. 7.3
  8. 7.4
  9. 8.0
  10. 8.1
  11. 8.2
  12. 8.3
  13. 8.4
  14. 9.0
  15. 9.1
  16. 9.2
  17. 9.3
  18. 10.0
  19. 10.1
  20. 10.2
  21. 10.3
  22. 10.4
  23. 11.0
  24. 11.1
  25. 11.2
  26. 11.3
  27. 11.4
  28. 12.0
  29. 12.1
  30. 12.2
  31. 12.3
  32. 12.4
  33. 13.0–13.2
  34. 13.3–14.5
  35. 15.0–16.0

History

The sigsetmask() and sigblock() functions first appeared in 4.2BSD and have been deprecated.

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