Mex function not updated after recompile

I have a simple mex function, which calls another C++ function from a library. I compile the source with

    mex -cxx mymexfunction.cpp -I/some/include -L/some/lib -lmylib

The mylib library is dynamic (.so) and is linked itself against some other libraries (boost, OpenCV and some more).

The problem I am having is that once I have called the function mymexfunction once, it will not get updated when I recompile the source code. I have tried

    clear
    clear all
    clear functions
    clear fun('mymexfunction')
    munlock('mymexfunction')
    unloadlibrary('mymexfunction')

...but nothing helps! I have to restart Matlab in order to be able to see the updated mexfunction. Even if I delete the compiled mex file and recompile, I still get the old version of the mex function (not on disk, but in memory).

All is fine if I don't link against mylib, but I have no idea what could be the culprit that prevents the update. The library is unfortunately too large and too interwoven to remove single modules one by one.

Are there some known conditions which could cause such problems?

[Kaustubha Govind]

Could you try "clear mex" and see if that helps?

[Martin]

Thanks for your suggestion, but unfortunately that does not help either.

[Alec Jacobson]

Suffering for the same problem even in 2020a...wish this would be fixed or at least a solution provided.

Answer 1

[Jan]

If the mex-file is locked from inside by an mexLock, you have to unlock it from inside also: mexUnlock. You have to trigger this by a special input, e.g. nrhs==0 or similar.

[Joseph]

I have the same problem using Matlab 2019a under OS X 10.14.5. I tried mexUnlock but it didn't help.

[Alec Jacobson]

I don't understand this answer. If my code is not calling mexLock do I still need to call mexLock for matlab to recognize my recompiled mex function?

[James Tursa]

If the mex routine is calling mexLock, then I don't think you can clear it from the command line. This is to prevent dangling resources etc. Look in the mex routine documentation to find out the syntax to use for it to unlock itself.

[Alec Jacobson]

I'm not current calling mexLock at all in my code, but still suffer from this issue that matlab doesn't recognize the recompiled mex function unless I restart matlab.

[James Tursa]

You clear mex, but it is still showing up as in memory when you use inmem? And you have the source code and you know it is not locking itself?

[Alec Jacobson]

correct.

[Paul Rötzer]

I struggle the same problem on Matlab 2022b on MacOSX (M1) but only when i compile from "outside" of matlab, i.e. when i use cmake build script. For functions which i build "inside" matlab the update works.