SIGPROCMASK(2) Linux Programmer's Manual SIGPROCMASK(2)NAMEsigprocmask - examine and change blocked signals
SYNOPSIS
#include <signal.h>
int sigprocmask(int how, const sigset_t *set, sigset_t *oldset);
DESCRIPTIONsigprocmask() is used to change the signal mask, the set of currently
blocked signals. The behaviour of the call is dependent on the value
of how, as follows.
SIG_BLOCK
The set of blocked signals is the union of the current
set and the set argument.
SIG_UNBLOCK
The signals in set are removed from the current set of
blocked signals. It is legal to attempt to unblock a
signal which is not blocked.
SIG_SETMASK
The set of blocked signals is set to the argument set.
If oldset is non-null, the previous value of the signal mask is stored
in oldset.
If set is NULL, then the signal mask is unchanged (i.e., how is
ignored), but the current value of the signal mask is nevertheless
returned in oldset (it is not NULL).
The use of sigprocmask() is unspecified in a multithreaded process; see
pthread_sigmask(3).
RETURN VALUEsigprocmask() returns 0 on success and -1 on error.
ERRORS
EINVAL The value specified in how was invalid.
NOTES
It is not possible to block SIGKILL or SIGSTOP. Attempts to do so are
silently ignored.
If SIGBUS, SIGFPE, SIGILL, or SIGSEGV are generated while they are
blocked, the result is undefined, unless the signal was generated by
the kill(2), sigqueue(2), or raise(3).
See sigsetops(3) for details on manipulating signal sets.
CONFORMING TO
POSIX.1-2001.
SEE ALSOkill(2), pause(2), sigaction(2), signal(2), sigpending(2), sigproc‐
mask(2), sigqueue(2), sigsuspend(2), pthread_sigmask(3), sigsetops(3),
signal(7)Linux 2.6.13 2005-09-15 SIGPROCMASK(2)
