[apple/xnu.git] / bsd / man / man2 / sigprocmask.2

.\"	$NetBSD: sigprocmask.2,v 1.6 1995/02/27 12:37:33 cgd Exp $
.\"
.\" Copyright (c) 1983, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"	@(#)sigprocmask.2	8.1 (Berkeley) 6/4/93
.\"
.Dd June 4, 1993
.Dt SIGPROCMASK 2
.Os
.Sh NAME
.Nm sigprocmask
.Nd manipulate current signal mask
.Sh SYNOPSIS
.Fd #include <signal.h>
.Ft int
.Fn sigprocmask "int how" "const sigset_t *set" "sigset_t *oset"
.Sh DESCRIPTION
The
.Fn sigprocmask
function examines and/or changes the current signal mask (those signals
that are blocked from delivery).
Signals are blocked if they are members of the current signal mask set.
.Pp
If
.Fa set
is not null, the action of
.Fn sigprocmask
depends on the value of the parameter
.Fa how .
The signal mask is changed as a function of the specified
.Fa set
and the current mask.
The function is specified by
.Fa how
using one of the following values from
.Aq Pa signal.h :
.Bl -tag -width SIG_UNBLOCK
.It Dv SIG_BLOCK
The new mask is the union of the current mask and the specified
.Fa set .
.It Dv SIG_UNBLOCK
The new mask is the intersection of the current mask
and the complement of the specified
.Fa set .
.It Dv SIG_SETMASK
The current mask is replaced by the specified
.Fa set .
.El
.Pp
If
.Fa oset
is not null, it is set to
the previous value of the signal mask.
When
.Fa set
is null,
the value of
.Ar how
is insignificant and the mask remains unset
providing a way to examine the signal mask without modification.
.Pp
The system
quietly disallows
.Dv SIGKILL
or
.Dv SIGSTOP
to be blocked.
.Sh RETURN VALUES
A 0 value indicated that the call succeeded.  A -1 return value
indicates an error occurred and
.Va errno
is set to indicated the reason.
.Sh ERRORS
The
.Fn sigprocmask
call will fail and the signal mask will be unchanged if one
of the following occurs:
.Bl -tag -width Er
.It Bq Er EINVAL
.Fa how
has a value other than those listed here.
.El
.Sh SEE ALSO
.Xr kill 2 ,
.Xr sigaction 2 ,
.Xr sigsetops 3 ,
.Xr sigsuspend 2
.Sh STANDARDS
The
.Fn sigprocmask
function call is expected to
conform to
.St -p1003.1-88 .
Commit	Line	Data
9bccf70c A	1	.\" $NetBSD: sigprocmask.2,v 1.6 1995/02/27 12:37:33 cgd Exp $
	2	.\"
	3	.\" Copyright (c) 1983, 1991, 1993
	4	.\" The Regents of the University of California. All rights reserved.
	5	.\"
	6	.\" Redistribution and use in source and binary forms, with or without
	7	.\" modification, are permitted provided that the following conditions
	8	.\" are met:
	9	.\" 1. Redistributions of source code must retain the above copyright
	10	.\" notice, this list of conditions and the following disclaimer.
	11	.\" 2. Redistributions in binary form must reproduce the above copyright
	12	.\" notice, this list of conditions and the following disclaimer in the
	13	.\" documentation and/or other materials provided with the distribution.
	14	.\" 3. All advertising materials mentioning features or use of this software
	15	.\" must display the following acknowledgement:
	16	.\" This product includes software developed by the University of
	17	.\" California, Berkeley and its contributors.
	18	.\" 4. Neither the name of the University nor the names of its contributors
	19	.\" may be used to endorse or promote products derived from this software
	20	.\" without specific prior written permission.
	21	.\"
	22	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	23	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	24	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	25	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	26	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	27	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	28	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	29	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	30	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	31	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	32	.\" SUCH DAMAGE.
	33	.\"
	34	.\" @(#)sigprocmask.2 8.1 (Berkeley) 6/4/93
	35	.\"
	36	.Dd June 4, 1993
	37	.Dt SIGPROCMASK 2
	38	.Os
	39	.Sh NAME
	40	.Nm sigprocmask
	41	.Nd manipulate current signal mask
	42	.Sh SYNOPSIS
	43	.Fd #include <signal.h>
	44	.Ft int
	45	.Fn sigprocmask "int how" "const sigset_t set" "sigset_t oset"
	46	.Sh DESCRIPTION
	47	The
	48	.Fn sigprocmask
	49	function examines and/or changes the current signal mask (those signals
	50	that are blocked from delivery).
	51	Signals are blocked if they are members of the current signal mask set.
	52	.Pp
	53	If
	54	.Fa set
	55	is not null, the action of
	56	.Fn sigprocmask
	57	depends on the value of the parameter
	58	.Fa how .
	59	The signal mask is changed as a function of the specified
	60	.Fa set
	61	and the current mask.
	62	The function is specified by
	63	.Fa how
	64	using one of the following values from
65	.Aq Pa signal.h :
66	.Bl -tag -width SIG_UNBLOCK
67	.It Dv SIG_BLOCK
68	The new mask is the union of the current mask and the specified
69	.Fa set .
70	.It Dv SIG_UNBLOCK
71	The new mask is the intersection of the current mask
72	and the complement of the specified
73	.Fa set .
74	.It Dv SIG_SETMASK
75	The current mask is replaced by the specified
76	.Fa set .
77	.El
78	.Pp
79	If
80	.Fa oset
81	is not null, it is set to
82	the previous value of the signal mask.
83	When
84	.Fa set
85	is null,
86	the value of
87	.Ar how
88	is insignificant and the mask remains unset
89	providing a way to examine the signal mask without modification.
90	.Pp
91	The system
92	quietly disallows
93	.Dv SIGKILL
94	or
95	.Dv SIGSTOP
96	to be blocked.
97	.Sh RETURN VALUES
98	A 0 value indicated that the call succeeded. A -1 return value
99	indicates an error occurred and
100	.Va errno
101	is set to indicated the reason.
102	.Sh ERRORS
103	The
104	.Fn sigprocmask
105	call will fail and the signal mask will be unchanged if one
106	of the following occurs:
107	.Bl -tag -width Er
108	.It Bq Er EINVAL
109	.Fa how
110	has a value other than those listed here.
111	.El
112	.Sh SEE ALSO
113	.Xr kill 2 ,
114	.Xr sigaction 2 ,
115	.Xr sigsetops 3 ,
116	.Xr sigsuspend 2
117	.Sh STANDARDS
118	The
119	.Fn sigprocmask
120	function call is expected to
121	conform to
122	.St -p1003.1-88 .