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SIGPROCMASK(2) BSD System Calls Manual SIGPROCMASK(2) NAME sigprocmask -- manipulate current signal mask LIBRARY Standard C Library (libc, -lc) SYNOPSIS #include <signal.h> int sigprocmask(int how, const sigset_t * restrict set, sigset_t * restrict oset); DESCRIPTION The sigprocmask() system call examines and/or changes the current signal mask (those signals that are blocked from delivery). Signals are blocked if they are members of the current signal mask set. If set is not null, the action of sigprocmask() depends on the value of the how argument. The signal mask is changed as a function of the speci- fied set and the current mask. The function is specified by how using one of the following values from <signal.h>: SIG_BLOCK The new mask is the union of the current mask and the speci- fied set. SIG_UNBLOCK The new mask is the intersection of the current mask and the complement of the specified set. SIG_SETMASK The current mask is replaced by the specified set. If oset is not null, it is set to the previous value of the signal mask. When set is null, the value of how is insignificant and the mask remains unset providing a way to examine the signal mask without modification. The system quietly disallows SIGKILL or SIGSTOP to be blocked. In threaded applications, pthread_sigmask(3) must be used instead of sigprocmask(). RETURN VALUES The sigprocmask() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error. ERRORS The sigprocmask() system call will fail and the signal mask will be un- changed if one of the following occurs: [EINVAL] The how argument has a value other than those listed here. SEE ALSO kill(2), sigaction(2), sigpending(2), sigsuspend(2), fpsetmask(3), pthread_sigmask(3), sigsetops(3) STANDARDS The sigprocmask() system call is expected to conform to ISO/IEC 9945-1:1990 ("POSIX.1"). BSD May 7, 2010 BSD
NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | SEE ALSO | STANDARDS
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