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sigprocmask(2) [sunos man page]

sigprocmask(2)															    sigprocmask(2)

sigprocmask - change or examine caller's signal mask SYNOPSIS
#include <signal.h> int sigprocmask(int how, const sigset_t *restrict set, sigset_t *restrict oset); The sigprocmask() function is used to examine and/or change the caller's signal mask. If the value is SIG_BLOCK, the set pointed to by the set argument is added to the current signal mask. If the value is SIG_UNBLOCK, the set pointed by the set argument is removed from the current signal mask. If the value is SIG_SETMASK, the current signal mask is replaced by the set pointed to by the set argument. If the oset argument is not NULL, the previous mask is stored in the space pointed to by oset. If the value of the set argument is NULL, the value how is not significant and the caller's signal mask is unchanged; thus, the call can be used to inquire about currently blocked sig- nals. If the set or oset argument points to an invalid address, the behavior is undefined and errno may be set to EFAULT. If there are any pending unblocked signals after the call to sigprocmask(), at least one of those signals will be delivered before the call to sigprocmask() returns. It is not possible to block signals that cannot be caught or ignored (see sigaction(2)). It is also not possible to block or unblock SIG- CANCEL, as SIGCANCEL is reserved for the implementation of POSIX thread cancellation (see pthread_cancel(3C) and cancellation(5)). This restriction is silently enforced by the standard C library. If sigprocmask() fails, the caller's signal mask is not changed. Upon successful completion, 0 is returned. Otherwise, -1 is returned and errno is set to indicate the error. The sigprocmask() function will fail if: EINVAL The value of the how argument is not equal to one of the defined values. The sigprocmask() function may fail if: EFAULT The set or oset argument points to an illegal address. See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |Async-Signal-Safe | +-----------------------------+-----------------------------+ sigaction(2), pthread_cancel(3C), pthread_sigmask(3C), signal(3C), signal.h(3HEAD), sigsetops(3C), attributes(5), cancellation(5) The call to sigprocmask() affects only the calling thread's signal mask. It is identical to a call to pthread_sigmask(3C). Signals that are generated synchronously should not be masked. If such a signal is blocked and delivered, the receiving process is killed. 23 Mar 2005 sigprocmask(2)

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SIGSETMASK(3)						   BSD Library Functions Manual 					     SIGSETMASK(3)

sigsetmask -- set current signal mask LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <signal.h> int sigsetmask(int mask); sigmask(signum); DESCRIPTION
This interface is made obsolete by: sigprocmask(2). sigsetmask() sets the current signal mask Signals are blocked from delivery if the corresponding bit in mask is a 1; the macro sigmask() is provided to construct the mask for a given signum. The system quietly disallows SIGKILL or SIGSTOP to be blocked. RETURN VALUES
The previous set of masked signals is returned. EXAMPLES
The following example using sigsetmask(): int omask; omask = sigblock(sigmask(SIGINT) | sigmask(SIGHUP)); ... sigsetmask(omask & ~(sigmask(SIGINT) | sigmask(SIGHUP))); Could be converted literally to: sigset_t set, oset; sigemptyset(&set); sigaddset(&set, SIGINT); sigaddset(&set, SIGHUP); sigprocmask(SIG_BLOCK, &set, &oset); ... sigdelset(&oset, SIGINT); sigdelset(&oset, SIGHUP); sigprocmask(SIG_SETMASK, &oset, NULL); Another, clearer, alternative is: sigset_t set; sigemptyset(&set); sigaddset(&set, SIGINT); sigaddset(&set, SIGHUP); sigprocmask(SIG_BLOCK, &set, NULL); ... sigprocmask(SIG_UNBLOCK, &set, NULL); To completely clear the signal mask using sigsetmask() one can do: (void) sigsetmask(0); Which can be expressed via sigprocmask(2) as: sigset_t eset; sigemptyset(&eset); (void) sigprocmask(SIG_SETMASK, &eset, NULL); SEE ALSO
kill(2), sigaction(2), sigprocmask(2), sigsuspend(2), sigblock(3), sigsetops(3), sigvec(3) HISTORY
The sigsetmask() function call appeared in 4.2BSD and has been deprecated. BSD
August 10, 2002 BSD

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