Using 'set_clock_groups' without parameter -asynchronous or -exclusive?

Hi,

From the Quartus user manual "Quartus II Handbook Version 9.1 Volume 3: Verification":

set_clock_groups

[-asynchronous | -exclusive]

-group <clock name>

[-group <clock name>]

[-group <clock name>] ...

a group is defined with the -group option. the timequest timing analyzer cuts the

timing paths between clocks each of the separate -groups groups.

I tried to use following constrain in SDC file:

set_clock_groups

-group [get_clocks {CLK_A}]

-group [get_clocks {CLK_B}]

But TimeQuest still reports violation of paths between

domain CLK_A and CLK_B.

Am I miss-understanding something???

# . PS: NO violation is reported if I use:

set_clock_groups -asynchronous

-group [get_clocks {CLK_A}]

-group [get_clocks {CLK_B}]

OR

set_clock_groups -exclusive

-group [get_clocks {CLK_A}]

-group [get_clocks {CLK_B}]