SIGSUSPEND(2) System Calls SIGSUSPEND(2)


NAME


sigsuspend - install a signal mask and suspend caller until signal

SYNOPSIS


#include <signal.h>

int sigsuspend(const sigset_t *set);


DESCRIPTION


The sigsuspend() function replaces the caller's signal mask with the set
of signals pointed to by the set argument and suspends the caller until
delivery of a signal whose action is either to execute a signal catching
function or to terminate the process. If the set argument points to an
invalid address, the behavior is undefined and errno may be set to
EFAULT.


If the action is to terminate the process, sigsuspend() does not return.
If the action is to execute a signal catching function, sigsuspend()
returns after the signal catching function returns. On return, the signal
mask is restored to the set that existed before the call to
sigsuspend().


It is not possible to block signals that cannot be ignored (see
signal.h(3HEAD)). This restriction is silently imposed by the system.

RETURN VALUES


Since sigsuspend() suspends the caller's execution indefinitely, there is
no successful completion return value. On failure, it returns -1 and sets
errno to indicate the error.

ERRORS


The sigsuspend() function will fail if:

EINTR
A signal was caught by the caller and control was returned from
the signal catching function.


The sigsuspend() function may fail if:

EFAULT
The set argument points to an illegal address.


ATTRIBUTES


See attributes(5) for descriptions of the following attributes:


+--------------------+-------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------+
|Interface Stability | Standard |
+--------------------+-------------------+
|MT-Level | Async-Signal-Safe |
+--------------------+-------------------+

SEE ALSO


sigaction(2), sigprocmask(2), sigwait(2), signal(3C), signal.h(3HEAD),
sigsetops(3C), attributes(5)

NOTES


If the caller specifies more than one unblocked signal in the mask to
sigsuspend(), more than one signal might be processed before the call to
sigsuspend() returns.


While the caller is executing the signal handler that interrupted its
call to sigsuspend(), its signal mask is the one passed to sigsuspend(),
modified as usual by the signal mask specification in the signal's
sigaction(2) parameters. The caller's signal mask is not restored to its
previous value until the caller returns from all the signal handlers that
interrupted sigsuspend().


June 24, 2001 SIGSUSPEND(2)