Question about max syscall number

[chuli]

Hi,

  When I use "auditctl -a exit,always -S 2015" in x86 system, this rule can be 
added.
But I thought it would report error since there is not such syscall number "1000"
in x86, the max is 318. If I use "auditctl -a exit,always -S 2016" in x86 system, 
it will report " Syscall name unknown: 2016". And it is the same with x86_64 and 
ia64.
(syscalls in S390 and ppc syscall table is 1-318)

  Is there any special reason to set the limitation as "2015"?

Regards
Chu Li