ASE 15.7 SP110
Example: known values: dbid=20, page#=161, indexid=2
1> select pageinfo (20,161,'4')
2> go
-----------
NULL
1> select pageinfo(20,161,'index id')
2> go
-----------
2
So, looks like the option name (eg, 'index id') has to be supplied as opposed to the option# (eg, '4'). Still, a nice-to-know function.