[Octave-bug-tracker] [bug #59597] bogus result returned by mexCallMATLAB

[Sébastien Villemot]

URL:
  <https://savannah.gnu.org/bugs/?59597>

                 Summary: bogus result returned by mexCallMATLAB
                 Project: GNU Octave
            Submitted by: svillemot
            Submitted on: mer. 02 déc. 2020 15:56:38 UTC
                Category: Interpreter
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Regression
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
                 Release: 6.1.0
         Discussion Lock: Any
        Operating System: GNU/Linux

    _______________________________________________________

Details:

Hi,

I have spent several hours debugging a regression in Octave 6, without success
so far.

The problem manifests with Dynare (see https://www.dynare.org), for which
I’m upstream developer.

Essentially the scenario is the following one. We have a MEX file, which
itself calls a given M-file function through mexCallMATLAB(). The first two
runs of the MEX file go fine, but the third time, the return values of the
function, as returned by mexCallMATLAB() are bogus: mxGetClassID() executed on
them returns 0, same for mxGetM() and mxGetN().

I’ve used valgrind to see if I could spot any illegal memory access, but
nothing of the like.

I’ve also tried to reduce the problem to a minimal test case, but without
success. More precisely, I’ve created a MEX file that only calls the M-file,
and then I executed that MEX file several times in a row, but this does not
trigger the problem. This probably means that the problem comes from the
interaction with other computations that are done by Dynare.

Note that the same code works fine under Octave 5.2.0 (and MATLAB), so this is
clearly a regression.

I would be grateful if someone could give me advice on how to further debug
this, because I’ve run out of ideas…





    _______________________________________________________

Reply to this item at:

  <https://savannah.gnu.org/bugs/?59597>

_______________________________________________
  Message posté via Savannah
  https://savannah.gnu.org/