SIGSUSPEND
Section: Linux Programmer's Manual (2)
Updated: 2017-09-15
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NAME
sigsuspend, rt_sigsuspend - wait for a signal
SYNOPSIS
#include <signal.h>
int sigsuspend(const sigset_t *mask);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
sigsuspend():
_POSIX_C_SOURCE
DESCRIPTION
sigsuspend()
temporarily replaces the signal mask of the calling process with the
mask given by
mask
and then suspends the process until delivery of a signal whose
action is to invoke a signal handler or to terminate a process.
If the signal terminates the process, then
sigsuspend()
does not return.
If the signal is caught, then
sigsuspend()
returns after the signal handler returns,
and the signal mask is restored to the state before the call to
sigsuspend().
It is not possible to block
SIGKILL
or
SIGSTOP;
specifying these signals in
mask,
has no effect on the process's signal mask.
RETURN VALUE
sigsuspend()
always returns -1, with
errno
set to indicate the error (normally,
EINTR).
ERRORS
- EFAULT
-
mask
points to memory which is not a valid part of the process address space.
- EINTR
-
The call was interrupted by a signal;
signal(7).
CONFORMING TO
POSIX.1-2001, POSIX.1-2008.
NOTES
Normally,
sigsuspend()
is used in conjunction with
sigprocmask(2)
in order to prevent delivery of a signal during the execution of a
critical code section.
The caller first blocks the signals with
sigprocmask(2).
When the critical code has completed, the caller then waits for the
signals by calling
sigsuspend()
with the signal mask that was returned by
sigprocmask(2)
(in the
oldset
argument).
See
sigsetops(3)
for details on manipulating signal sets.
C library/kernel differences
The original Linux system call was named
sigsuspend().
However, with the addition of real-time signals in Linux 2.2,
the fixed-size, 32-bit
sigset_t
type supported by that system call was no longer fit for purpose.
Consequently, a new system call,
rt_sigsuspend(),
was added to support an enlarged
sigset_t
type.
The new system call takes a second argument,
size_t sigsetsize,
which specifies the size in bytes of the signal set in
mask.
This argument is currently required to have the value
sizeof(sigset_t)
(or the error
EINVAL
results).
The glibc
sigsuspend()
wrapper function hides these details from us, transparently calling
rt_sigsuspend()
when the kernel provides it.
SEE ALSO
kill(2),
pause(2),
sigaction(2),
signal(2),
sigprocmask(2),
sigwaitinfo(2),
sigsetops(3),
sigwait(3),
signal(7)
COLOPHON
This page is part of release 4.13 of the Linux
man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
https://www.kernel.org/doc/man-pages/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- CONFORMING TO
-
- NOTES
-
- C library/kernel differences
-
- SEE ALSO
-
- COLOPHON
-
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