Procedure SigAction (Signum : Integer; Var Act,OldAct : PSigActionRec) ;
Changes the action to take upon receipt of a signal. Act and Oldact are pointers to a SigActionRec record.
SigNum specifies the signal, and can be any signal except SIGKILL or SIGSTOP.
If Act is non-nil, then the new action for signal SigNum is taken from it. If OldAct is non-nil, the old action is stored there.
Sa_Handler may be SIG_DFL for the default action or SIG_IGN to ignore the signal.
Sa_Mask Specifies which signals should be ignord during the execution of the signal handler.
Sa_Flags Speciefies a series of flags which modify the behaviour of the signal handler. You can 'or' none or more of the following :
LinuxError is used to report errors.
SigProcMask, SigPending, SigSuspend, Kill, Sigaction (2)