1 

Disallows NULL input. This prevents the user from responding to the request by entering only [Return] or a space.

2

Disallows input of zero (0). This prevents the user from responding to the request by entering 0.

4

Disallows negative values. This prevents the user from responding to the request by entering a negative value.

8

Does not check drawing limits, even if the LIMCHECK system variable is on. This enables the user to enter a point outside the current drawing limits. This condition applies to the next user-input function even if the AutoCAD LIMCHECK system variable is currently set.

16

Not currently used.

32

Uses dashed lines when drawing rubber-band lines or boxes. This causes the rubber-band line or box that AutoCAD displays to be dashed instead of solid, for those methods that let the user specify a point by selecting a location on the graphics screen. (Some display drivers use a distinctive color instead of dashed lines.) If the POPUPS system variable is 0, AutoCAD ignores this bit.

64

Ignores Z coordinate of 3D points (GetDistance method only). This option ignores the Z coordinate of 3D points returned by the GetDistance method, so an application can ensure this function returns a 2D distance.

128

Allows arbitrary input—whatever the user types.