SIGBLOCK(3B)                                                      SIGBLOCK(3B)


NAME
     sigblock - block signals from delivery to process (4.3BSD)

SYNOPSIS
     #include <signal.h>

     int sigblock(int mask);

     mask = sigmask(int signum);

     To use any of the BSD signal routines (kill(3B), killpg(3B),
     sigvec(3B)) you must either

     1) #define _BSD_SIGNALS or _BSD_COMPAT before including <signal.h>, or

     2) specify one of them in the compile command or makefile:

          cc -D_BSD_SIGNALS -o prog prog.c


DESCRIPTION
     sigblock causes the signals specified in mask to be added to the set of
     signals currently being blocked from delivery.  Signals are blocked if
     the corresponding bit in mask is a 1 (numbering the bits from 1 to 32);
     the macro sigmask is provided to construct the mask for a given signum.

     It is not possible to block SIGKILL, SIGSTOP, or SIGCONT; this
     restriction is imposed silently by the system.

RETURN VALUE
     The previous set of masked signals is returned.

SEE ALSO
     kill(3B), sigvec(3B), sigsetmask(3B), signal(5).

WARNING (IRIX)
     The 4.3BSD and System V signal facilities have different semantics.
     Using both facilities in the same program is strongly discouraged and
     will result in unpredictable behavior.


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