minix/lib/libc/gen/siginterrupt.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

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Groff

.\" $NetBSD: siginterrupt.3,v 1.11 2003/08/07 16:42:56 agc Exp $
.\"
.\" Copyright (c) 1985, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
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.\" @(#)siginterrupt.3 8.1 (Berkeley) 6/4/93
.\"
.Dd June 4, 1993
.Dt SIGINTERRUPT 3
.Os
.Sh NAME
.Nm siginterrupt
.Nd allow signals to interrupt system calls
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In signal.h
.Ft int
.Fn siginterrupt "int sig" "int flag"
.Sh DESCRIPTION
The
.Fn siginterrupt
function
is used to change the system call restart
behavior when a system call is interrupted by the specified signal.
If the flag is false (0), then system calls will be restarted if
they are interrupted by the specified signal
and no data has been transferred yet.
System call restart is the default behavior on
.Bx 4.2 .
.Pp
If the flag is true (1),
then restarting of system calls is disabled.
If a system call is interrupted by the specified signal
and no data has been transferred,
the system call will return \-1 with the global variable
.Va errno
set to
.Dv EINTR .
Interrupted system calls that have started transferring
data will return the amount of data actually transferred.
System call interrupt is the signal behavior found on
.Bx 4.1
and
.At V
systems.
.Pp
Note that the new
.Bx 4.2
signal handling semantics are not
altered in any other way.
Most notably, signal handlers always remain installed until
explicitly changed by a subsequent
.Xr sigaction 2
call, and the signal mask operates as documented in
.Xr sigaction 2 .
Programs may switch between restartable and interruptible
system call operation as often as desired in the execution of a program.
.Pp
Issuing a
.Fn siginterrupt 3
call during the execution of a signal handler will cause
the new action to take place on the next signal to be caught.
.Sh NOTES
This library routine uses an extension of the
.Xr sigaction 2
system call that is not available in
.Bx 4.2 ,
hence it should not be used if backward compatibility is needed.
.Sh RETURN VALUES
A 0 value indicates that the call succeeded.
A \-1 value indicates that an invalid signal number has been supplied.
.Sh SEE ALSO
.Xr sigaction 2 ,
.Xr sigprocmask 2 ,
.Xr sigsuspend 2
.Sh HISTORY
The
.Fn siginterrupt
function appeared in
.Bx 4.3 .