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);
intmask;
int sigmask( signum);
int signum;
int sigpause(int mask);
int mask;
int sigsetmask( mask);
int mask;
DESCRIPTION
sigblock, sigmask, sigpause, sigsetmask - block signals
sigblock() 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 construct 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 critical 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
sigblock().
It is not possible to block SIGKILL, SIGSTOP, or SIGCONT, this restriction is silently imposed by the system.
RETURN VALUES
sigblock() and sigsetmask() return the previous set of masked signals. sigpause() returns -1 and sets errno to EINTR.
SEE ALSO
kill(2), sigaction(2), signal(3UCB), sigvec(3UCB)
NOTES
Use of these interfaces should be restricted to only applications written on BSD platforms. Use of these interfaces with any of the system
libraries or in multi-thread applications is unsupported.
SunOS 5.10 19 Feb 1993 sigblock(3UCB)