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sigvec(2)							    sigvec(2)

  sigvec - Provides a compatibility interface to the sigaction() function


  #include <&lt;sys/signal.h>&gt;
  int sigvec (
	  int signal,
	  struct sigvec	*in_vec,
	  struct sigvec	*out_vec );


  signal    Specifies the signal number.

  in_vec    Points to a	sigvec() structure that	specifies the action to	be
	    taken when the specified signal is delivered, the mask to be used
	    when calling the signal handler, and the flags that	modify signal

  out_vec   Points to a	sigvec() structure that	is set to the previous signal
	    action state on successful return from the sigvec()	function.


  The sigvec() function	is provided for	compatibility to old UNIX systems;
  its function is a subset of that available with the sigaction() function.
  Like the sigaction() function, the sigvec() function allows the user to set
  the action to	take upon the receipt of a signal and to specify a signal
  handler mask to block	signals	before calling the signal handler. However,
  only signals with values 1 to	31 can be masked on entry to a signal-handler
  set up with the sigvec() function.

  The sigvec() structure has the following members:
       void    (*sv_handler)( );
       int     sv_mask;
       int     sv_flags;

  The sv_handler field specifies the action for	the signal, and	can be
  SIG_DFL, SIG_IGN, or the address of a	signal handler function. See the
  sigaction() function for a detailed description of the signal	actions.

  The sv_mask field specifies a	mask which specifies signals to	block (in
  addition to any signals already blocked at time of delivery) when the	sig-
  nal handler function is called for the signal.  Signal i is blocked if the
  i-th bit of the mask is set. Only signals with values	1 to 31	can be masked
  with the sigvec() function.  The sv_flags field contains flags that further
  specify signal behavior.  If SV_ONSTACK is set, the signal handler runs on
  the signal stack specified by	the sigstack() function;  otherwise, the sig-
  nal handler runs on the stack	of the process receiving the signal.  If
  SV_INTERRUPT is set, a system	call that is interrupted by signal returns a
  value	of -1 with errno set to	[EINTR];  otherwise, a system call inter-
  rupted by signal is restarted.

  If the value of the in_vec parameter is a null pointer, then the signal
  handler information is not set. If the value of the out_vec parameter	is
  null,	then the previous signal handler information is	not returned.

  Once a signal	handler	is assigned, it	remains	assigned until another call
  to the sigvec(), signal(), sigaction(), or exec function is made.


  The sigvec() function	is provided for	compatibility only, and	its use	is
  not recommended.   Programs should use the sigaction() function instead.

  The sigvec() function	does not check the validity of the sv_handler field
  pointer. If it points	to a location outside of the process address space,
  the process receives a memory	fault when the system attempts to call the
  signal handler. If the sv_handler field points to anything other than	a
  function, the	results	are unpredictable.

  The signal-handler function can be declared as follows:
       void handler (
	       int signal );


  Upon successful completion, a	value of 0 (zero) is returned.	If the
  sigvec() function fails, a value of -1 is returned and errno is set to
  indicate the error.


  If the sigvec() function fails, no new signal	handler	is installed and
  errno	may be set to one of the following values:

  [EFAULT]  The	in_vec or out_vec parameter points to a	location outside of
	    the	process' address space.

  [EINVAL]  The	signal parameter is not	a valid	signal number.

  [EINVAL]  An attempt was made	to ignore or supply a handler for the SIGKILL


  Functions: kill(2), ptrace(2), sigaction(2), sigblock(2), sigpause(3), sig-