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SIGPAUSE(2) | System Calls Manual | SIGPAUSE(2) |
NAME¶
sighold
,
sigignore
,
sigpause
,
sigrelse
,
sigset
—
legacy interface for signal management
LIBRARY¶
Standard C Library (libc, -lc)SYNOPSIS¶
#include
<signal.h>
int
sighold
(int
sig);
int
sigignore
(int
sig);
int
xsi_sigpause
(int
sigmask);
int
sigrelse
(int
sig);
void (*)(int)
sigset
(int,
void
(*disp)(int));
int
sigpause
(int
sigmask);
DESCRIPTION¶
This interface is made obsolete by sigsuspend(2) and sigaction(2). Thesigset
() function modifies signal
dispositions. The sig argument specifies the
signal, which may be any signal except
SIGKILL
and
SIGSTOP
. The
disp argument specifies the signal's
disposition, which may be SIG_DFL
,
SIG_IGN
, or the address of a signal
handler. If sigset
() is used, and
disp is the address of a signal handler, the
system adds sig to the signal mask of the
calling process before executing the signal handler; when the signal handler
returns, the system restores the signal mask of the calling process to its
state prior to the delivery of the signal. In addition, if
sigset
() is used, and
disp is equal to
SIG_HOLD
,
sig is added to the signal mask of the
calling process and sig 's disposition
remains unchanged. If sigset
() is used, and
disp is not equal to
SIG_HOLD
,
sig is removed from the signal mask of the
calling process.
The sighold
() function adds
sig to the signal mask of the calling
process.
The sigrelse
() function removes
sig from the signal mask of the calling
process.
The sigignore
() function sets the disposition
of sig to
SIG_IGN
.
The xsi_sigpause
() function removes
sig from the signal mask of the calling
process and suspend the calling process until a signal is received. The
xsi_sigpause
() function restores the signal
mask of the process to its original state before returning.
The sigpause
() function assigns
sigmask to the set of masked signals and then
waits for a signal to arrive; on return the set of masked signals is restored.
The sigmask argument is usually 0 to indicate
that no signals are to be blocked.
RETURN VALUES¶
Thesigpause
() and
xsi_sigpause
() functions always terminate
by being interrupted, returning -1 with errno
set to EINTR
.
Upon successful completion, sigset
() returns
SIG_HOLD
if the signal had been blocked and
the signal's previous disposition if it had not been blocked. Otherwise,
SIG_ERR
is returned and
errno set to indicate the error.
For all other functions, upon successful completion, 0 is returned. Otherwise,
-1 is returned and errno is set to indicate
the error:
- [
EINVAL
] - The sig argument is not a valid signal number.
- [
EINVAL
] - For
sigset
() andsigignore
() functions, an attempt was made to catch or ignoreSIGKILL
orSIGSTOP
.
SEE ALSO¶
kill(2), sigaction(2), sigblock(2), sigprocmask(2), sigsuspend(2), sigvec(2)STANDARDS¶
Thesigpause
() function is implemented for
compatibility with historic 4.3BSD applications. An
incompatible interface by the same name, which used a single signal number
rather than a mask, was present in AT&T System V
UNIX, and was copied from there into the
X/Open System Interfaces (XSI) option of
IEEE Std 1003.1-2001
(“POSIX.1”). FreeBSD implements
it under the name xsi_sigpause
(). The
sighold
(),
sigignore
(),
sigrelse
() and
sigset
() functions are implemented for
compatibility with System V and
XSI interfaces.
HISTORY¶
Thesigpause
() function appeared in
4.2BSD and has been deprecated. All other functions
appeared in FreeBSD 8.1 and were deprecated before
being implemented.June 2, 1993 | Debian |