Node:Blocking in BSD, Previous:BSD Handler, Up:BSD Signal Handling
| int sigmask (int signum) | Macro | 
This macro returns a signal mask that has the bit for signal signum
set.  You can bitwise-OR the results of several calls to sigmask
together to specify more than one signal.  For example,
(sigmask (SIGTSTP) | sigmask (SIGSTOP) | sigmask (SIGTTIN) | sigmask (SIGTTOU)) specifies a mask that includes all the job-control stop signals.  | 
| int sigblock (int mask) | Function | 
This function is equivalent to sigprocmask (see Process Signal Mask) with a how argument of SIG_BLOCK: it adds the
signals specified by mask to the calling process's set of blocked
signals.  The return value is the previous set of blocked signals. 
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| int sigsetmask (int mask) | Function | 
This function equivalent to sigprocmask (see Process Signal Mask) with a how argument of SIG_SETMASK: it sets
the calling process's signal mask to mask.  The return value is
the previous set of blocked signals. 
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| int sigpause (int mask) | Function | 
This function is the equivalent of sigsuspend (see Waiting for a Signal):  it sets the calling process's signal mask to mask,
and waits for a signal to arrive.  On return the previous set of blocked
signals is restored. 
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