minix/lib/libc/compat-43/sigblock.3
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

119 lines
3.2 KiB
Groff

.\" Copyright (c) 1983, 1991, 1993
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.\" 3. 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.
.\"
.\" from: @(#)sigblock.2 8.1 (Berkeley) 6/2/93
.\" $NetBSD: sigblock.3,v 1.17 2003/08/07 16:42:40 agc Exp $
.\"
.Dd August 10, 2002
.Dt SIGBLOCK 3
.Os
.Sh NAME
.Nm sigblock
.Nd block signals
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In signal.h
.Ft int
.Fn sigblock "int mask"
.Ft int
.Fn sigmask signum
.Sh DESCRIPTION
.Bf -symbolic
This interface is made obsolete by:
.Xr sigprocmask 2 .
.Ef
.Pp
.Fn sigblock
adds the signals specified in
.Fa mask
to the set of signals currently
being blocked from delivery.
Signals are blocked if the
corresponding bit in
.Fa mask
is a 1; the macro
.Fn sigmask
is provided to construct the mask for a given
.Fa signum .
.Pp
It is not possible to block
.Dv SIGKILL
or
.Dv SIGSTOP ;
this restriction is silently
imposed by the system.
.Sh RETURN VALUES
The previous set of masked signals is returned.
.Sh EXAMPLES
The following example using
.Fn sigblock :
.Bd -literal -offset indent
int omask;
omask = sigblock(sigmask(SIGINT) | sigmask(SIGHUP));
.Ed
.Pp
Becomes:
.Bd -literal -offset indent
sigset_t set, oset;
sigemptyset(&set);
sigaddset(&set, SIGINT);
sigaddset(&set, SIGHUP);
sigprocmask(SIG_BLOCK, &set, &oset);
.Ed
.Pp
Another use of
.Fn sigblock
is to get the current set of masked signals without changing what
is actually blocked.
Instead of:
.Bd -literal -offset indent
int set;
set = sigblock(0);
.Ed
.Pp
Use the following:
.Bd -literal -offset indent
sigset_t set;
sigprocmask(SIG_BLOCK, NULL, &set);
.Ed
.Sh SEE ALSO
.Xr kill 2 ,
.Xr sigaction 2 ,
.Xr sigprocmask 2 ,
.Xr sigsetmask 3 ,
.Xr sigsetops 3
.Sh HISTORY
The
.Fn sigblock
function call appeared in
.Bx 4.2
and has been deprecated.