August 10, 2002 SIGSETMASK 3

### NAME

sigsetmask - set current signal mask

### LIBRARY

Standard C Library (libc, -lc)

### SYNOPSIS

```int` sigsetmask(```int mask`) sigmask(```signum`)

### DESCRIPTION

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

sigsetmask(``) sets the current signal mask Signals are blocked from delivery if the corresponding bit in ```mask` is a 1; 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 previous set of masked signals is returned.

### EXAMPLES

The following example using sigsetmask(``):

  `

      int omask;

      omask = sigblock(sigmask(SIGINT) | sigmask(SIGHUP));

      ...

      sigsetmask(omask & ~(sigmask(SIGINT) | sigmask(SIGHUP)));

  `

Could be converted literally to:

  `

      sigset_t set, oset;

      sigemptyset(&set);
      sigaddset(&set, SIGINT);
      sigaddset(&set, SIGHUP);
      sigprocmask(SIG_BLOCK, &set, &oset);

      ...

      sigdelset(&oset, SIGINT);
      sigdelset(&oset, SIGHUP);
      sigprocmask(SIG_SETMASK, &oset, NULL);

  `

Another, clearer, alternative is:

  `

      sigset_t set;

      sigemptyset(&set);
      sigaddset(&set, SIGINT);
      sigaddset(&set, SIGHUP);
      sigprocmask(SIG_BLOCK, &set, NULL);

      ...

      sigprocmask(SIG_UNBLOCK, &set, NULL);

  `

To completely clear the signal mask using sigsetmask(``) one can do:

  `

      (void) sigsetmask(0);

  `

Which can be expressed via sigprocmask(2) as:

  `

      sigset_t eset;

      sigemptyset(&eset);
      (void) sigprocmask(SIG_SETMASK, &eset, NULL);

  `

### SEE ALSO

kill(2), sigaction(2), sigprocmask(2), sigsuspend(2), sigblock(3), sigsetops(3), sigvec(3)

### HISTORY

The sigsetmask(``) function call appeared in 4.2BSD and has been deprecated.