sigset, sighold, sigrelse, sigignore - Compatibility
interfaces for signal management
#include <sys/signal.h>
void (*sigset(
int signal,
void (*function) (int))) (int ); int sighold(
int signal ); int sigrelse(
int signal ); int sigignore(
int signal );
Standard C Library (libc)
Interfaces documented on this reference page conform to
industry standards as follows:
sigset(), sighold(), sigrelse(), sigignore(): XSH4.2
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
Specifies the signal. The signal parameter can be
assigned any of the signals defined in the signal.h header
file, except SIGKILL and SIGSTOP. Specifies one of four
values: SIG_DFL, SIG_IGN, SIG_HOLD, or an address of a
signal-catching function. The function() parameter is
declared as type pointer to a function returning void.
The sigset(), sighold(), sigrelse(), and sigignore() functions
provide simplified signal management.
The sigset() function is used to modify signal dispositions.
The value of the function parameter determines the
system signal action to be taken upon receipt of signal,
as follows: If function is the address of a signal-catching
function, the system adds signal to the calling process'
signal mask before executing the signal-catching
function. When the signal-catching function returns, the
system restores the calling process' signal mask to its
state prior to delivery of the signal. If function is
equal to SIG_HOLD, signal is added to the calling process'
signal mask and the disposition of signal remains
unchanged. If function is not SIG_HOLD, signal is removed
from the calling process' signal mask.
The sighold() function adds signal to the calling process'
signal mask.
The sigrelse() function removes signal from the calling
process' signal mask.
The sigignore() function sets the disposition of signal to
SIG_IGN.
The sighold() function, in conjunction with sigrelse and
sigpause(), may be used to establish critical regions of
code that require the delivery of a signal to be temporarily
deferred.
These interfaces are provided for compatibility only. New
programs should use sigaction() and sigprocmask() to control
the disposition of signals.
[Tru64 UNIX] When compiled in the X/Open UNIX environment,
calls to the sigset() function are internally
renamed by prepending _E to the function name. When you
are debugging a module that includes the sigset() function
and for which _XOPEN_SOURCE_EXTENDED has been defined, use
_Esigset to refer to the sigset() call. See standards(5)
for information on when the _XOPEN_SOURCE_EXTENDED macro
is defined.
Upon successful completion, the sigset() function returns
the previous value of the system signal action for the
specified signal. Otherwise, it returns SIG_ERR and errno
is set to indicate the error.
For the sighold(), sigrelse(), and sigignore() functions,
a value of 0 (zero) is returned upon success. Otherwise, a
value of -1 is returned and errno is set to indicate the
error.
The sigset(), sighold(), sigrelse(), and sigignore() functions
set errno to the specified values for the following
conditions: The signal parameter is either an illegal signal
number or SIGKILL, or the default handling of signal
cannot be changed.
Functions: kill(2), setjmp(3), sigaction(2), sigpause(3),
sigprocmask(2), wait(2)
Files: signal(4)
Standards: standards(5)
sigset(3)
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