- Returns the maximum signo value for which a corresponding symbolic
- name or message is available. Note that in the case where
- we use the sys_siglist supplied by the system, it is possible for
- there to be more symbolic names than messages, or vice versa.
- In fact, the manual page for psignal(3b) explicitly warns that one
- should check the size of the table (NSIG) before indexing it,
- since new signal codes may be added to the system before they are
- added to the table. Thus NSIG might be smaller than value
- implied by the largest signo value defined in <signal.h>.
-
- We return the maximum value that can be used to obtain a meaningful
- symbolic name or message.