Constructs the mask for a given signal number.

    Format

      #include  <signal.h>

      int sigmask  (signum);

1 - Argument

 signum

    The signal number for which the mask is to be constructed.

2 - Description

    The sigmask function is used to construct the mask for a given
    signum. This mask can be used with the sigblock function.

3 - Return Value

    x                  The mask constructed for signum