MWMCR exception - Attempted to read or write protected memory.

I have made a Matlab .dll with my .NET builder, but when i try to access the class MDClass in my namespace MelanomaDetection get the following error:

{"The type initializer for 'MelanomaDetection.MDClass' threw an exception."}

Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

MWArray at MathWorks.MATLAB.NET.Utility.MWMCR.mclIsMCRInitialized() at MathWorks.MATLAB.NET.Utility.MWMCR..cctor()

I just initialize it like this:

var m = new MDClass();

I don't have any restrictions in my Matlab program, neither in my .NET app.

Thanks in advance for any help!

Answer 1

[Kaustubha Govind]

Have you copied mclmcrrt7x.dll to a location outside of the MCR installation directory? It looks like that could cause this error: http://www.mathworks.com/support/solutions/en/data/1-AN5VOX/index.html

[Kim]

I have included it in my project.

Before the above error, i got the error that it was missing, so i added it, and it disappeared :)

[Kaustubha Govind]

The right think to do is to add the path to the mclmcrrt7x.dll to the system PATH variable. You need to install the MCR and then add mcr_root\ver\runtime\win32|win64 to the top of the system path. See http://www.mathworks.com/help/toolbox/compiler/f12-999353.html#br2jauc-34

[Kim]

It looks like it is already added: "C:\Program Files (x86)\MATLAB\MATLAB Compiler Runtime\v715\runtime\win32".

I'm running on a 64-bit w7, and im executing my code on a 64-bit Windows Server 2008 R2.

Could this have any effect?

[Kaustubha Govind]

Yes! You need to have the 64-bit MCR installed and added to path.

[Kim]

Even when my Matlab runs 32-bit?

[Kaustubha Govind]

No, if you're compiling with 32-bit MATLAB, you need 32-bit MCR.

[Kim]

Okay, then could it be my runtime environment that is wrong? is there any special features you have to set up?

I'm running the newest MCR 7.16, and my .dll has been compiled in Matlab 2011b, so that should fit.

The MCR still crashes though...

[Kaustubha Govind]

Kim: Perhaps it will be best if you contact MathWorks Tech Support about this, since you seemed to have tried a lot of things already?

Answer 2

[Guy]

I've discovered a problem with mclIsMCRInitialized(), and raised it here some four months ago, in that if you try to call this function and the MCR is not initialized, then it doesn't return 0 as documented, but rather crashes with a segmentation fault. This doesn't make it terrible useful. I'd be interested to know if you're testing the return value of this function in order to then decide whether to call mclInitializeApplication(). If so, then it sounds like the same issue and I can only suggest forcing an initial MCR initialization, rather than making it conditional on a returned value of 0 from mclIsMCRInitialized().

[Kim]

I can't seem to force an MCR initialization, how would you do this?

I've tried with InitializeApplication() but it doesn't seem to work.