Subject: Understanding SDS compatibility

The primary difference between ADS and SDS is that all SDS functions have an sds_ prefix, and ADS functions have a variety of prefixes, such as ads_, acad_, and acrx_. The exception is dialog-related SDS functions, which have a dlg_ prefix. CADdirect accepts either prefix. Other differences include the additional SDS functions listed in the following table.

SDS functions with no ADS equivalent

SDS function name



Clears all graphics from the drawing window; similar to the LISP (grclear) function.


Clears the entity name or selection set.


Verifies whether two entity names or selection sets are equal.


Verifies whether the entity name or selection set has been cleared.


Copies one entity name or selection set to another drawing.


Similar to the ads_ssget function, but allows you to display a prompt appropriate for the specific command, rather than the generic “Select object” prompt.


Copies a point from one variable to another.


Displays the percentage done in a progress bar.


Starts the progress bar.


Ends the progress bar.


Loads the PGP file into CADdirect.


Sends a message to the CADdirect command line.


Flips the off-screen device context to the display.

Some ADS functions are not supported in SDS, including: ads_arxload, ads_arxloaded, ads_arxunload, ads_ssgetx, ads_ssGetKwordCallbackPtr, ads_ssGetOtherCallbackPtr, adsw_acadMainWnd, and adsw_acadDocWnd.

To automatically run an SDS custom application when CADdirect starts

   1   Create an ASCII file named icad.sds that contains the path to the .dll files on each line of the file.

   2   Place icad.sds in the same folder as icad.exe.

   3   Run CADdirect.

For more information

   Read the online documentation for SDS functions.

   See the \CADdirect\Api\Sds folder, which contains the SDS include, header, and library files.

   See the \CADdirect\Api\Dcl folder, which contains the core DCL files.

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