minix/lib/libc/sys/sigprocmask.2
Ben Gras 2fe8fb192f Full switch to clang/ELF. Drop ack. Simplify.
There is important information about booting non-ack images in
docs/UPDATING. ack/aout-format images can't be built any more, and
booting clang/ELF-format ones is a little different. Updating to the
new boot monitor is recommended.

Changes in this commit:

	. drop boot monitor -> allowing dropping ack support
	. facility to copy ELF boot files to /boot so that old boot monitor
	  can still boot fairly easily, see UPDATING
	. no more ack-format libraries -> single-case libraries
	. some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases
	. drop several ack toolchain commands, but not all support
	  commands (e.g. aal is gone but acksize is not yet).
	. a few libc files moved to netbsd libc dir
	. new /bin/date as minix date used code in libc/
	. test compile fix
	. harmonize includes
	. /usr/lib is no longer special: without ack, /usr/lib plays no
	  kind of special bootstrapping role any more and bootstrapping
	  is done exclusively through packages, so releases depend even
	  less on the state of the machine making them now.
	. rename nbsd_lib* to lib*
	. reduce mtree
2012-02-14 14:52:02 +01:00

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.\" $NetBSD: sigprocmask.2,v 1.22 2006/01/07 20:11:30 kleink Exp $
.\"
.\" Copyright (c) 1983, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
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.\" notice, this list of conditions and the following disclaimer in the
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.\" without specific prior written permission.
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.\"
.\" @(#)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 LIBRARY
.Lb libc
.Sh SYNOPSIS
.In signal.h
.Ft int
.Fn sigprocmask "int how" "const sigset_t * restrict set" "sigset_t * restrict 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:
.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.
.Pp
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 indicates that the call succeeded.
A \-1 return value indicates an error occurred and
.Va errno
is set to indicate 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 sigsuspend 2 ,
.Xr pthread_sigmask 3 ,
.Xr sigsetops 3 ,
.Xr signal 7
.Sh STANDARDS
The
.Fn sigprocmask
function conforms to
.St -p1003.1-90 .