[Gdal-dev] Re: Memory leak under Matlab (a follow up from - importFromWkt() problem)

[Mateusz Loskot]

Joaquim Luis wrote:
> 
> Hi, I was following this thread with a particular interest due to 
> another problem. I wrote a OGR based Matlab MEX file to do coordinate
>  conversions. Well the thing works well but has a small memory leak. 
> Though small, the leak is sufficiently important to prevent the use 
> of that program when attached to mouse movements (it accumulates 
> fast).

Joaquin,

Sounds strange. Is there any chance you're misusing MEX memory
management functions or may be you're following one of MATLAB
buggy examples, like:
http://www.mathworks.com/support/solutions/data/1-1NOXOX.html

May be you're using mexMakeMemoryPersistent in loop or similar call,
so memory is not cleared after your MEX is unloaded.
Note, it's only my surmise.

> Now given the valgrind report about the test prog "importwkt" I 
> converted it into a ML mex and, ... the memory leak is still there. 
> To be honest a similar story happened with a GMT based mex file to do
>  also coordinate conversions, so I'm starting to lean to the 
> probability that the problem might be on the Matlab side (a third 
> attempt with a OpenCV mex also reveals some memory leak) .

Are you using MATLAB on Windows?
Have you tried to run your MEX with a memory leak checker attached?
If you're using MATLAB on Windows, I'd try to build MEX dll with
VLD leak detector [1] but I'm not sure if it will give you usable
and meaningful report when working with MATLAB.

[1] http://www.codeproject.com/tools/visualleakdetector.asp

Another option is to do some simple  tests of memory
allocation/deallocation and observe how MATLAB will behave.

> However, guessing that it wont be nothing at all easy to convince 
> Mathworks about this problem I'm asking here about the chances that 
> it might be a GDAL memory leak.

IMHO contacting Mathworks support and sending them your MEX code
would be the easiest, but I don't know if effective.

There are chances for memory leaks in GDAL as in every other piece
software. Not much helpful, but thats all I can say.

Cheers
-- 
Mateusz Loskot
http://mateusz.loskot.net