mirror of https://github.com/mkerrisk/man-pages
104 lines
2.9 KiB
Groff
104 lines
2.9 KiB
Groff
.\" Copyright (c) 2007 Michael Kerrisk <mtk.manpages@gmail.com>
|
|
.\"
|
|
.\" %%%LICENSE_START(VERBATIM)
|
|
.\" Permission is granted to make and distribute verbatim copies of this
|
|
.\" manual provided the copyright notice and this permission notice are
|
|
.\" preserved on all copies.
|
|
.\"
|
|
.\" Permission is granted to copy and distribute modified versions of this
|
|
.\" manual under the conditions for verbatim copying, provided that the
|
|
.\" entire resulting derived work is distributed under the terms of a
|
|
.\" permission notice identical to this one.
|
|
.\"
|
|
.\" 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.\" manual page may be incorrect or out-of-date.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
|
|
.\" have taken the same level of care in the production of this manual,
|
|
.\" which is licensed free of charge, as they might when working
|
|
.\" professionally.
|
|
.\"
|
|
.\" Formatted or processed versions of this manual, if unaccompanied by
|
|
.\" the source, must acknowledge the copyright and authors of this work.
|
|
.\" %%%LICENSE_END
|
|
.\"
|
|
.TH SYSV_SIGNAL 3 2017-09-15 "" "Linux Programmer's Manual"
|
|
.SH NAME
|
|
sysv_signal \- signal handling with System V semantics
|
|
.SH SYNOPSIS
|
|
.BR "#define _GNU_SOURCE" " /* See feature_test_macros(7) */"
|
|
.br
|
|
.B #include <signal.h>
|
|
.PP
|
|
.B typedef void (*sighandler_t)(int);
|
|
.PP
|
|
.BI "sighandler_t sysv_signal(int " signum ", sighandler_t " handler );
|
|
.SH DESCRIPTION
|
|
The
|
|
.BR sysv_signal ()
|
|
function takes the same arguments, and performs the same task, as
|
|
.BR signal (2).
|
|
.PP
|
|
However
|
|
.BR sysv_signal ()
|
|
provides the System V unreliable signal semantics, that is:
|
|
a) the disposition of the signal is reset to the default
|
|
when the handler is invoked;
|
|
b) delivery of further instances of the signal is not blocked while
|
|
the signal handler is executing; and
|
|
c) if the handler interrupts (certain) blocking system calls,
|
|
then the system call is not automatically restarted.
|
|
.SH RETURN VALUE
|
|
The
|
|
.BR sysv_signal ()
|
|
function returns the previous value of the signal handler, or
|
|
.B SIG_ERR
|
|
on error.
|
|
.SH ERRORS
|
|
As for
|
|
.BR signal (2).
|
|
.SH ATTRIBUTES
|
|
For an explanation of the terms used in this section, see
|
|
.BR attributes (7).
|
|
.TS
|
|
allbox;
|
|
lb lb lb
|
|
l l l.
|
|
Interface Attribute Value
|
|
T{
|
|
.BR sysv_signal ()
|
|
T} Thread safety MT-Safe
|
|
.TE
|
|
.SH CONFORMING TO
|
|
This function is nonstandard.
|
|
.SH NOTES
|
|
Use of
|
|
.BR sysv_signal ()
|
|
should be avoided; use
|
|
.BR sigaction (2)
|
|
instead.
|
|
.PP
|
|
On older Linux systems,
|
|
.BR sysv_signal ()
|
|
and
|
|
.BR signal (2)
|
|
were equivalent.
|
|
But on newer systems,
|
|
.BR signal (2)
|
|
provides reliable signal semantics; see
|
|
.BR signal (2)
|
|
for details.
|
|
.PP
|
|
The use of
|
|
.I sighandler_t
|
|
is a GNU extension;
|
|
this type is defined only if
|
|
the
|
|
.B _GNU_SOURCE
|
|
feature test macro is defined.
|
|
.SH SEE ALSO
|
|
.BR sigaction (2),
|
|
.BR signal (2),
|
|
.BR bsd_signal (3),
|
|
.BR signal (7)
|