Summary
The sigprocmask() function allows the calling process to examine or change (or both) the signal mask of the calling thread.
1
If the argument set is not a null pointer, it points to a set of signals to be used to change the currently blocked set.
1
The sigprocmask() function is used to examine and/or change the caller's signal mask.
2
If the value is SIG_BLOCK, the set pointed to by the set argument is added to the current signal mask.
2
If the value is SIG_UNBLOCK, the set pointed by the set argument is removed from the current signal mask.
2
The sigprocmask command is used to fetch and/or change the signal mask of a calling thread.
3
The signal mask is the set of signals whose delivery is currently blocked for the caller, and the behavior of the call is dependent on the value of how.
3
It is not possible to block SIGKILL or SIGSTOP, and tries to do so are silently ignored.
3
The sigprocmask() function examines and/or changes the current signal mask (those signals that are blocked from delivery).
4
Signals are blocked if they are members of the current signal mask set.
4
If set is not null, the action of sigprocmask() depends on the value of the parameter how.
4
According to
