[Octave-bug-tracker] [bug #61813] memory management bug when calling MEX that returns an output

[John W. Eaton]

Update of bug #61813 (project octave):

                  Status:                    None => Patch Submitted        

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Follow-up Comment #9:

The attached change fixes the problem for me.  It reverts to always copy
unless we are using the polymorphic allocator and avoids allowing Octave to
delete data transferred from an mxArray to an octave_value object unless it is
done when returning from a MEX function call.

The problem was that in handing off ownership of the data in an mxArray object
with a single element to an octave_value object, the octave_value object may
mutate from an array to a scalar object and then the mxArray data would be
deleted.  That obviously causes trouble if the mxArray data is needed again
after it is used by by Octave in the octave_value object as was the case in
the example (the rhs data used after calling mexCallMATLAB).

I'll create a proper (set of) changeset(s) soon and commit on stable.




(file #52896)
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Additional Item Attachment:

File name: mx-2-ov-alloc-diffs.txt        Size:7 KB
    <https://file.savannah.gnu.org/file/mx-2-ov-alloc-diffs.txt?file_id=52896>



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