46 — AutoLISP API Deprecation & Breakage Risk Reference¶

Note

This document catalogs every deprecated, removed, or silently-changed AutoLISP function, sysvar, and API surface since AutoCAD 2000 (R15). Use this as a pre-commit risk checklist when writing or reviewing AutoLISP code. Cross-reference against 30 — AutoCAD Evolution Analysis: Version-by-Version Impact on ConstructiVision for version-sequenced context and Bug Tracker — Validation Campaign for known ConstructiVision bugs rooted in these changes.

1. Dead Functions — Hardware Feature Removed¶

These functions still parse and may return nil without error, but target hardware or UI infrastructure that no longer exists.

Function	Lost Since	Why
`tablet`	~2014	Digitizing tablet support removed. Calibration calls accepted but affect nothing.
`grtext` (positive slot indices)	2006	Screen menu tile areas removed with CUI migration. Positive slot writes silently no-op. Slot `-1` (status bar) behavior varies by version — test before using.
`slide_image`	~2000s	`.sld` slide files are a pre-R14 format. `MSLIDE` still exists but no current tooling produces slides. Function works if you have a `.sld` file; you never will.
`graphscr`	~R14	Switched to graphics screen in dual-screen pre-R14 mode. Unified single-window UI since R14 — no-op.
`textscr`	~R14	Switched to text screen — same.
`textpage`	~R14	Cleared and displayed the text screen — same.

Risk for ConstructiVision: Low. None of these appear in TB11 source. Old startup code in customer customizations may still call grtext — document as a known no-op if raised.

2. VBA Removal — Broken on 2025+¶

Function	Broken Since	Notes
`vl-vbaload`	AutoCAD 2025	Loaded a `.dvb` VBA project. VBA was optionally installable from 2014; fully removed in 2025. Throws on 2025+.
`vl-vbarun`	AutoCAD 2025	Ran a named VBA macro. Same — calls into a runtime that no longer exists.

Risk for ConstructiVision: Low. CV does not use VBA. Risk exists only in customer environments where CV coexists with VBA-dependent customizations.

3. ActiveX / COM — Crashes .NET Core Runtime (2025+)¶

Warning

This is the highest-severity breakage in the entire deprecation surface. These functions are NOT removed from the AutoLISP reference — they are silently broken at runtime. Code that worked correctly on AutoCAD 2000–2024 throws ACCESS_VIOLATION (0xC0000005) in coreclr.dll on AutoCAD 2025+. See Bug 93, DFMEA-035.

Unsafe — Crash on 2025+¶

Function / Pattern	Notes
`vla-get-ActiveDocument`	COM property access — crashes
`vlax-get-acad-object`	Entry point for COM object model — crashes
`vlax-get-property`	COM property dispatch — crashes
`vlax-put-property`	COM property write — crashes
`vlax-invoke-method`	COM method call — crashes
`vlax-create-object`	Creates COM object instance — crashes
`vla-*` (any property/method)	All COM property and method calls — crashes

Safe on All Versions¶

Function	Notes
`vl-load-com`	Loads the VLISP COM runtime module — safe. The objects it enables are unsafe, not this loader.
`vlax-product-key`	VLISP built-in returning a registry path string — not a COM call.
`vlax-curve-*`	Geometric utility functions — not COM dispatch.
`vlax-safearray-*`	Safearray data structure helpers — not COM dispatch.
`vlax-tmatrix`	Transformation matrix helpers — not COM dispatch.

Mandatory Guard Pattern¶

Defined in csvcompat.lsp. Use before any vla-* or COM-chain call:

;; csv_is-dotnet-core returns T when ACADVER >= 25.0
(if (not (csv_is-dotnet-core))
  (progn
    (vl-load-com)
    (vla-some-method ...)
  )
  ;; .NET Core safe fallback — use (command ...) instead
  (command "_.COMMANDNAME" ...)
)

Preferred alternative for ALL versions: (command "_.CMD" ...) with filedia=0. Works universally from AutoCAD 2000 through 2027+. No VLA fallback needed.

4. Memory Management — No-Ops Since ~R15¶

These were performance tuning knobs for the fixed node-pool LISP heap used in R10–R14. AutoCAD 2000 (R15) introduced dynamic heap management — these functions are accepted but have no effect. They are a maintenance hazard because they signal intent that is never honored.

Function	Old Purpose	Current Behavior
`alloc`	Pre-allocate LISP node segments	No-op
`expand`	Expand node pool by N segments	No-op
`mem`	Report node/string pool statistics	Returns data; values are meaningless on dynamic heap
`gc`	Force garbage collection	Runtime GCs automatically; calling this never hurts but never helps either

Risk for ConstructiVision: Low. Remove any instances on sight — they signal a cargo-cult copy from pre-R15 startup code and may confuse future maintainers.

5. Superseded Functions — Valid But Wrong for New Code¶

Still functional, but there is a better option that should be used in all new code.

Old Function	Problem	Use Instead
`ver`	Returns human-readable string `"AutoCAD VLISP 16.1"` — format is not stable	`(getvar "ACADVER")` — returns parseable string like `"25.0"`
`setcfg`	Writes to `acad.cfg` — file location moved in 2014+; writes may be ignored	NOD XRecords (`dictadd`/`dictsearch`) for drawing data; `vl-registry-write` for profile data
`getcfg`	Reads from `acad.cfg` — values may not be present on modern profiles	Same replacements as `setcfg`
`initdia`	Forced next `(command ...)` call to show file dialog regardless of `FILEDIA`	`(setvar "FILEDIA" 1)` before the call, or design to the default dialog-on behavior

6. Menu Infrastructure — Degraded Since 2006/2010¶

Function	Status	Notes
`menucmd` (screen menu macros `$S=`, `$T=`)	No-op since 2006	Screen menu removed with CUI migration. Any `menucmd` call using `$S=` or `$T=` notation silently does nothing.
`menucmd` (toolbar/other)	Partially works	Ribbon-era CUI behavior differs from `.mnu` era. Test on target version before relying on it.
`menugroup`	Degraded	Returns loaded menu group names. Works, but menu architecture changed from `.mnu`/`.mnc` to `.cuix` in 2010. Results differ.
`acad_helpdlg`	Degraded	Help system moved online in 2013. The CHM topic path syntax expected by this function may not resolve to a local file on current installs.

7. Sysvar Breakages — Dimension Variables¶

These are the most dangerous category for ConstructiVision because the product generates dimensions. Silent data corruption risk: old code writing the old sysvar writes to a live but ignored variable; the controlling sysvar holds a stale or default value.

Superseded in AutoCAD 2002¶

Old Sysvar	Replaced By	Breaking Detail
`DIMFIT` (0–5)	`DIMATFIT` (0–3) + `DIMTMOVE` (0–2)	The 6-state fit scale was split into two orthogonal controls. Mapping is not 1:1. Old code writing `(setvar "DIMFIT" 3)` is accepted without error but the actual behavior is controlled by `DIMATFIT`/`DIMTMOVE`, not `DIMFIT`.
`DIMUNIT` (1–5)	`DIMLUNIT` (1–6)	Stacked fractions added as format 4, shifting all values above it by one slot. `DIMUNIT 4` (architectural) ≠ `DIMLUNIT 4` (fractional). Old code reads back wrong format.
`DIMASO` (0/1)	`DIMASSOC` (0/1/2)	`DIMASSOC` gained a third state (1 = exploded but retaining definition points). Old `(setvar "DIMASO" 1)` maps to `DIMASSOC 2`, not `DIMASSOC 1`. Code testing for associativity with `(= (getvar "DIMASO") 1)` reads a deprecated var and may get a wrong answer.

Added in AutoCAD 2002 — Did Not Exist in R2000¶

Sysvar	Notes
`DIMTDEC`	Controls tolerance decimal places independently of `DIMDEC`. R2000 code that used `DIMDEC` to control tolerance decimal display is now only controlling dimension text decimals — tolerance display precision is governed separately.

Behavior Changed — DIMSCALE = 0 (AutoCAD 2008)¶

In AutoCAD 2000–2007: DIMSCALE = 0 was effectively undefined — no documented behavior, should never be set intentionally.

In AutoCAD 2008+: DIMSCALE = 0 became the annotative dimension flag. Setting it enables annotative scaling for the current dimension style.

Breaking pattern:

;; R2000-era guard treating 0 as "bad input":
(if (= (getvar "DIMSCALE") 0)
  (setvar "DIMSCALE" 1)   ; "fix" corrupted value
)
;; On 2008+, this guard destroys a legitimately set annotative style
;; by resetting it to non-annotative.

8. Sysvar Breakages — Frame Variables (Silent Ternary Expansion)¶

These changed from binary (0/1) to ternary (0/1/2) to support “display but do not plot” as a third state. Old code testing (= (getvar "IMAGEFRAME") 1) misses state 2 and treats a visible-but-not-plotted frame as if frames are off.

Sysvar	Old Range	New Range	Since
`IMAGEFRAME`	0/1	0/1/2	~2007
`XCLIPFRAME`	0/1	0/1/2	~2007
`WIPEOUTFRAME`	0/1	0/1/2	~2009
`PDFFRAME`	—	0/1/2	2010 (new)
`DGNFRAME`	—	0/1/2	2010 (new)

Risk for ConstructiVision: Moderate. CV uses image entities (site photos, panel diagrams). Any code that sets or tests IMAGEFRAME must use > 0 rather than = 1 to correctly detect “frames visible.”

9. Sysvar Removals — Throws on Modern AutoCAD¶

These sysvars no longer exist. Calling (setvar "BLIPMODE" 0) on a modern AutoCAD throws error: unknown variable name. This pattern is common in old startup code that tries to clean up drawing state.

Sysvar	Removed	Notes
`BLIPMODE`	~2006	Blip marks feature removed.
`MENUECHO`	~2010	Suppressed menu macro echo to command line. Menu architecture gone.

Safe pattern for old startup code that may run on multiple versions:

(vl-catch-all-apply 'setvar '("BLIPMODE" 0))
(vl-catch-all-apply 'setvar '("MENUECHO" 0))

11. Coverage Gaps¶

This document covers three of four API surfaces. The fourth requires separate research:

Surface	Coverage
AutoLISP functions	✅ Covered (Sections 1–6)
System variables	✅ Covered (Sections 7–9)
DXF group code changes per entity type	❌ Not yet documented — required before entmake/entmod refactor
ARX/ObjectARX behavior affecting `arxload`-based utilities	❌ Not applicable to current CV build (no `.arx` dependencies)

DXF group code changes are tracked as a prerequisite in XData Refactor Plan — Eliminate Text File Serialization.

Last Updated: May 5, 2026