112 lines
3.9 KiB
Groff
112 lines
3.9 KiB
Groff
.\" Copyright (c) 1985, 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.
|
|
.\"
|
|
.\" @(#)siginterrupt.3 8.1 (Berkeley) 6/4/93
|
|
.\"
|
|
.Dd June 4, 1993
|
|
.Dt SIGINTERRUPT 3
|
|
.Os BSD 4.3
|
|
.Sh NAME
|
|
.Nm siginterrupt
|
|
.Nd allow signals to interrupt system calls
|
|
.Sh SYNOPSIS
|
|
.Fd #include <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 has been the default behavior since
|
|
.Bx 4.2 ,
|
|
and is the default behaviour for
|
|
.Xr signal 3
|
|
on
|
|
.Tn FreeBSD .
|
|
.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 sigblock 2 ,
|
|
.Xr sigpause 2 ,
|
|
.Xr sigsetmask 2 ,
|
|
.Xr signal 3
|
|
.Sh HISTORY
|
|
The
|
|
.Fn siginterrupt
|
|
function appeared in
|
|
.Bx 4.3 .
|