Re: Segfault loading draw.lisp (GCL b ackend) — draw2d/draw3d/gr2d unusable on Debian/Ubunt u-packaged Maxima 5.49.0

On Fri, Aug 21 2026, Jean-Michel Sarlat <[email protected]> wrote:

> Hi Robert, and everyone else who chimed in,
>
>  Thanks for the help — and to everyone who reported hitting the same
>  load(draw) segfault, that made the diagnosis much easier to trust.
>
>  These issues showed up while updating pmaxima (old script from the
> Syracuse site)
>  — a client/server setup, Maxima run persistently
>  via -s PORT rather than one-shot batch calls, which is where both of the
>  following surfaced.
>
> Tested on Maxima 5.49.0+dsfg-2 (Debian), GCL 2.7.1:
>
>  1. (mk:oos "draw" :compile) -> (mk:oos "draw" :load) in draw.lisp does
>      fix the segfault, but not durably: mk:defsystem recompiles whenever
>      the source is newer than the cached .o (package upgrade, or any local
>      edit), so the crash comes back. More robust: skip mk:defsystem/oos
>      entirely and load the four files directly:
>
>        (let ((dir (maxima-load-pathname-directory)))
>          (load (merge-pathnames (make-pathname :name "grcommon" :type
> "lisp") dir))
>          (load (merge-pathnames (make-pathname :name "gnuplot"  :type
> "lisp") dir))
>          (load (merge-pathnames (make-pathname :name "vtk"      :type
> "lisp") dir))
>          (load (merge-pathnames (make-pathname :name "picture"  :type
> "lisp") dir)))

Isn't it easier to install the build-essentials package?

>
>   2. With that fixed, draw2d(terminal=svg, ...) still failed:
>      "Cannot load input from '"/tmp/maxoutNNNNN.gnuplot"'" — even though
>      the file existed. Isolated independently of draw:
>
>        system("touch \"/tmp/foo.txt\"")
>
>      creates a file literally named "/tmp/foo.txt" (quotes included).
>      Maxima's system() under this GCL build doesn't strip escaped double
>      quotes before exec'ing. It hits draw because gnuplot.lisp's
>      file-output branch quotes the filename
>      (format nil "~a \"~a\"" $gnuplot_command gfn, two spots) — removing

Where are these commands? When I search share/draw/gnuplot.lisp and
src/gnuplot_def.lisp (HEAD), I can find none.

---

Btw, Yamwi re-defines the system command for {gcl,sbcl,ecl,clisp} in
order to smooth over several of the problems you might see like this
one. For the latter three, it uses `uiop/run-program:run-program', while
gcl needs to be special-cased.

Leo
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