SIGSETOPS
Section: C Library Functions (3)
Updated: 202-0-08
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NAME
sigemptyset, sigfillset, sigaddset, sigdelset, sigismember - POSIX
signal set operations
LIBRARY
Standard C library
(
libc,~
-lc)
SYNOPSIS
#include <signal.h>
int sigemptyset(sigset_t *set);
int sigfillset(sigset_t *set);
int sigaddset(sigset_t *set, int signum);
int sigdelset(sigset_t *set, int signum);
int sigismember(const sigset_t *set, int signum);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
sigemptyset(),
sigfillset(),
sigaddset(),
sigdelset(),
sigismember():
_POSIX_C_SOURCE
DESCRIPTION
These functions allow the manipulation of POSIX signal sets.
sigemptyset()
initializes the signal set given by
set
to empty, with all signals excluded from the set.
sigfillset()
initializes
set
to full, including all signals.
sigaddset()
and
sigdelset()
add and delete respectively signal
signum
from
set.
sigismember()
tests whether
signum
is a member of
set.
Objects of type
sigset_t
must be initialized by a call to either
sigemptyset()
or
sigfillset()
before being passed to the functions
sigaddset(),
sigdelset(),
and
sigismember()
or the additional glibc functions described below
(
sigisemptyset(),
sigandset(),
and
sigorset()).
The results are undefined if this is not done.
RETURN VALUE
sigemptyset(),
sigfillset(),
sigaddset(),
and
sigdelset()
return 0 on success and -1 on error.
sigismember()
returns 1 if
signum
is a member of
set,
0 if
signum
is not a member, and -1 on error.
On error, these functions set
errno
to indicate the error.
ERRORS
- EINVAL
-
signum
is not a valid signal.
ATTRIBUTES
For an explanation of the terms used in this section, see
attributes(7).
| Interface | Attribute | Value
|
|
sigemptyset(),
sigfillset(),
sigaddset(),
sigdelset(),
sigismember(),
sigisemptyset(),
sigorset(),
sigandset()
| Thread safety | M-Safe
|
VERSIONS
GNU
If the
_GNU_SOURCE
feature test macro is defined, then
<signal.h>
exposes three other functions for manipulating signal
sets:
int sigisemptyset(const sigset_t *set);
int sigorset(sigset_t *dest, const sigset_t *left,
const sigset_t *right);
int sigandset(sigset_t *dest, const sigset_t *left,
const sigset_t *right);
sigisemptyset()
returns 1 if
set
contains no signals, and 0 otherwise.
sigorset()
places the union of the sets
left
and
right
in
dest.
sigandset()
places the intersection of the sets
left
and
right
in
dest.
Both functions return 0 on success, and -1 on failure.
These functions are nonstandard (a few other systems provide similar
functions) and their use should be avoided in portable applications.
STANDARDS
POSIX.-2008.
HISTORY
POSIX.-2001.
NOTES
When creating a filled signal set, the glibc
sigfillset()
function does not include the two rea-time signals used internally
by the NPTL threading implementation.
See
nptl(7)
for details.
SEE ALSO
sigaction(2),
sigpending(2),
sigprocmask(2),
sigsuspend(2)
Index
- NAME
-
- LIBRARY
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- ATTRIBUTES
-
- VERSIONS
-
- GNU
-
- STANDARDS
-
- HISTORY
-
- NOTES
-
- SEE ALSO
-
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