SDI System Variable

ObjectARX provides a compatibility mode for the single drawing interface (SDI) of previous releases. It is controlled by the SDI system variable. Possible values for SDI are shown in the following table:

SDI system variable values
Value	Meaning
0	MDI is enabled
1	SDI mode set by user
2	SDI mode implied by loaded non–MDI-aware applications
3	SDI mode implied both by user and by loaded non–MDI-aware applications

Be aware of the following restrictions on changing the value of SDI:

• SDI can only be set to values of 2 or 3 by AutoCAD, as applications are loaded and unloaded.
• Always check the current value of SDI before making changes. If the current value is 2 or 3, do not change it.
• Changing SDI to 1 from 0 will fail when AutoCAD has more than one document open.

All document lock checking is disabled when AutoCAD is running in any of the SDI modes.