Access of a nested structure memory leak in mex function

[Evangelos Rozos]

The access of a nested structure passed to a mex function seems to 
create memory leak.

Example code:

 mxArray* pmx1=NULL;
 mxArray* pmxid=NULL;
 pmx1= mxGetField(prhs[0], 0, "InsDmd");
 pmxid= mxGetField(pmx1, 0, "id");        // <-- memory leak stops when 
commenting this out


This problem has been witnessed in Octave 5.1.0/win64 and Octave 
4.2.2/Linux (I believe exists in every platform and recent Octave 
version). The same code does not create leak when compiled in MATLAB.

Apparently, the indicated line code above does not create directly the 
leak, but somehow confuses the memory management. The leak is noticeable 
only after numerous calls of the mex function (7.6 MB/100000 calls).

Evangelos Rozos