sigblock(3UCB) SunOS/BSD Compatibility Library Functions sigblock(3UCB)NAME
sigblock, sigmask, sigpause, sigsetmask - block signals
SYNOPSIS
/usr/ucb/cc [ flag ... ] file ...
#include <signal.h>
int sigblock(mask)
int mask;
int sigmask(signum)
int signum;
int sigpause(mask)
int mask;
int sigsetmask(mask)
int mask;
DESCRIPTIONsigblock() adds the signals specified in mask to the set of signals
currently being blocked from delivery. Signals are blocked if the
appropriate bit in mask is a 1; the macro sigmask is provided to con‐
struct the mask for a given signum. sigblock() returns the previous
mask. The previous mask may be restored using sigsetmask().
sigpause() assigns mask to the set of masked signals and then waits for
a signal to arrive; on return the set of masked signals is restored.
mask is usually 0 to indicate that no signals are now to be blocked.
sigpause() always terminates by being interrupted, returning −1 and
setting errno to EINTR.
sigsetmask() sets the current signal mask (those signals that are
blocked from delivery). Signals are blocked if the corresponding bit
in mask is a 1; the macro sigmask is provided to construct the mask for
a given signum.
In normal usage, a signal is blocked using sigblock(). To begin a crit‐
ical section, variables modified on the occurrence of the signal are
examined to determine that there is no work to be done, and the process
pauses awaiting work by using sigpause() with the mask returned by sig‐
block().
It is not possible to block SIGKILL, SIGSTOP, or SIGCONT, this
restriction is silently imposed by the system.
RETURN VALUESsigblock() and sigsetmask() return the previous set of masked signals.
sigpause() returns −1 and sets errno to EINTR.
SEE ALSOcc(1B), kill(2), sigaction(2), signal(3UCB), sigvec(3UCB)NOTES
Use of these interfaces should be restricted to only applications writ‐
ten on BSD platforms. Use of these interfaces with any of the system
libraries or in multi-thread applications is unsupported.
SunOS 5.10 30 Oct 2007 sigblock(3UCB)
