.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\"
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.\" manual provided the copyright notice and this permission notice are
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.\" entire resulting derived work is distributed under the terms of a
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.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
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.\"
.\" References consulted:
.\"     Linux libc source code
.\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
.\"     386BSD man pages
.\" Modified Sun Jul 25 10:40:51 1993 by Rik Faith (faith@cs.unc.edu)
.\" Modified Sun Apr 14 16:20:34 1996 by Andries Brouwer (aeb@cwi.nl)
.TH SIGINTERRUPT 3 2009-03-15 "" "Linux Programmer's Manual"
.SH NAME
siginterrupt \- allow signals to interrupt system calls
.SH SYNOPSIS
.nf
.B #include <signal.h>
.sp
.BI "int siginterrupt(int " sig ", int " flag );
.fi
.sp
.in -4n
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
.sp
.BR siginterrupt ():
_BSD_SOURCE || _XOPEN_SOURCE\ >=\ 500
.SH DESCRIPTION
The
.BR siginterrupt ()
function changes the restart behavior when
a system call is interrupted by the signal \fIsig\fP.
If the \fIflag\fP
argument is false (0), then system calls will be restarted if interrupted
by the specified signal \fIsig\fP.
This is the default behavior in Linux.
However, when a new signal handler is specified with the
.BR signal (2)
function, the system call is interrupted by default.
.PP
If the \fIflag\fP argument is true (1) and no data has been transferred,
then a system call interrupted by the signal \fIsig\fP will return \-1
and \fIerrno\fP will be set to
.BR EINTR .
.PP
If the \fIflag\fP argument is true (1) and data transfer has started,
then the system call will be interrupted and will return the actual
amount of data transferred.
.SH "RETURN VALUE"
The
.BR siginterrupt ()
function returns 0 on success, or \-1 if the
signal number \fIsig\fP is invalid.
.SH ERRORS
.TP
.B EINVAL
The specified signal number is invalid.
.SH "CONFORMING TO"
4.3BSD, POSIX.1-2001.
POSIX.1-2008 marks
.BR siginterrupt ()
as obsolete, recommending the use of
.BR sigaction (2)
with the
.B SA_RESTART
flag instead.
.SH "SEE ALSO"
.BR signal (2)
.SH COLOPHON
This page is part of release 3.22 of the Linux
.I man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.
