Allows you to specify the action to take when a particular signal
    is raised.

    Format

      #include  <signal.h>

      void  (*ssignal (int sig, void (*func) (int, . . . )))
            (int, . . . );

1 - Arguments

 sig

    A number or mnemonic associated with a signal. The symbolic
    constants for signal values are defined in the <signal.h> header
    file. See the Error and Signal Handling chapter of the HP C RTL
    Reference Manual.

 func

    The action to take when the signal is raised, or the address of a
    function that is executed when the signal is raised.

2 - Description

    The ssignal function is equivalent to the signal function except
    for the return value on error conditions.

    Since the signal function is defined by the ANSI C standard and
    the ssignal function is not, use signal for greater portability.

    See the "Error and Signal Handling" chapter of the HP C RTL
    Reference Manual for more information on signal handling.

3 - Return Values

    x                  The address of the function previously
                       established as the action for the signal.
                       The address may be the value SIG_DFL (0)  or
                       SIG_IGN (1).
    0                  Indicates errors. For this reason, there is
                       no way to know whether a return status of 0
                       indicates failure, or whether it indicates
                       that a previous action was SIG_DFL (0).