invalid mex file and missing libmwblas.dylib error

I am compiling a MATLAB script on mac and i have downloaded Xcode for MEX file integration but I am getting the following error related to some missing libraries:

 Invalid MEX-file '/Users/haneya/Desktop/SVT_MostRecent/private/XonOmega.mexmaci64':
 dlopen(/Users/haneya/Desktop/SVT_MostRecent/private/XonOmega.mexmaci64, 6): Library not
 loaded: @loader_path/libmwblas.dylib

 Referenced from: /Users/haneya/Desktop/SVT_MostRecent/private/XonOmega.mexmaci64

 Reason: image not found.

[Walter Roberson]

Which Mac operating system are you using?

The library should be in fullfile(matlabroot, 'bin/maci64/libmwblas.dylib') but I suspect that is not on your library path, especially if you are using Sierra or High Sierra.

[Haneya Qureshi]

I am using macOS High Sierra Version 10.13.1

What should i do now?

[Walter Roberson]

You might be running into difficulties with Apple's System Integrity Protection (SIP), https://support.apple.com/en-ca/HT204899

It is not "supposed to" affect applications such as MATLAB that you install, but people are finding that it does.

What it does is disable paying attention to LD_LIBRARY_PATH for some executables. The work-around sometimes suggested is to put a copy of the library into /usr/lib

[Haneya Qureshi]

Thanks a lot for your suggestions! I copied the library from fullfile(matlabroot, 'bin/maci64/libmwblas.dylib') and placed it in the folder where my matlab script was and it's working perfectly now!

[Raymond MacNeil]

@Walter Roberson

Thanks, this fixed my issue.

[Samuel L. Polk]

@Walter Roberson Hello! I am having the same issue as Haneya. I put a copy of the library into the folder in which my MATLAB script that uses libmwblas.dylib is. However, I am still getting the same error. I was wondering if you have any other suggestions. Thank you!

My specific error is:

Invalid MEX-file
'/Users/sampolk/Documents/MATLAB/Code/DemoMatlabRealData/QPAS/qpas.mexmaci64':
dlopen('/Users/sampolk/Documents/MATLAB/Code/DemoMatlabRealData/QPAS/qpas.mexmaci64', 6): Library not
loaded: @loader_path/libmwblas.dylib
  Referenced from:
  /Users/sampolk/Documents/MATLAB/Code/DemoMatlabRealData/QPAS
  Reason: image not found 

[Walter Roberson]

You might have to put it into /usr/lib

[Samuel L. Polk]

@Walter Roberson Thank you for your quick response! Unfortunately, I'm having some trouble finding the folder '/user/lib/' in the package contents of the MATLAB software. Could you please describe where that folder is? I am runnning MATLAB R2021a on macOS Big Sur Version 11.2.3 if that is any help. Thank you again for your help.

[Walter Roberson]

It was /usr/lib not /user/lib . And it is not inside the MATLAB software, it is a system folder that exists on systems derived from Unix.

!ls /usr/lib

apt		dconf  gettext		 groff		  libgdiplus.so        libMonoPosixHelper.so  modules-load.d  pkg-config.multiarch  sasl2		 systemd     X11
binfmt.d	debug  girepository-1.0  initramfs-tools  libgdiplus.so.0      libMonoSupportW.so     mono	      python2.7		    sftp-server		 tar	     x86_64-linux-gnu
binfmt-support	dpkg   glib-networking	 insserv	  libgdiplus.so.0.0.0  locale		      openssh	      python3		    software-properties  tc	     xorg
cli		esmtp  gnupg		 jvm		  libid3tag.so.0       man-db		      os-release      python3.5		    ssl			 tmpfiles.d
compat-ld	gcc    gold-ld		 ldscripts	  libid3tag.so.0.3.0   mime		      pkgconfig       python3.8		    syslog-ng		 valgrind

However:

• in newer releases of MacOS, /usr/lib is controlled by System Integrity Protection, and it might be necessary to use csrutil to disable SIP to write to the directory
• starting from Big Sur, the root file system is "sealed", and you might need to unseal it, make the change to /usr/lib, and re-seal it afterwards; see https://eclecticlight.co/2020/06/25/big-surs-signed-system-volume-added-security-protection/
• I have seen a claim that you can write to /usr/local/lib instead of /usr/lib, and I see in the documentation for SIP that /usr/local is not protected. I do not know if this will work
• it looks like there may be approaches using install_name_change to modify MATLAB's idea of its library paths; https://briandfoy.github.io/macos-s-system-integrity-protection-sanitizes-your-environment/
• You might be able to modify rpath; see https://medium.com/@donblas/fun-with-rpath-otool-and-install-name-tool-e3e41ae86172
• However... although SIP is not supposed to affect MATLAB because it is not a "system executable" provided by Apple, in practice people observe that it does affect MATLAB because MATLAB is typically inside /Applications . And that implies that you might potentially need special steps to modify MATLAB's rpath .

Answer 1

[Omar Shadeed]

Hi Haneya,

I'm actually having the same error, I copied the libmwblas.dylib file from matlabroot and pasted it in my current matlab directory but I still get the same error.

Note: The mex is done successfully but when I run the Simulinknk model that uses the S-Function I get the same error you got. So what did you do to make it work?

Thanks,

The error I get is:

• Error while obtaining sizes from MEX S-function 'TrackerObject' in 'DSSDK_TrackerSingleObject/S-Function'.
• Caused by:
• Invalid MEX-file '/Users/omarshadeed/Desktop/VICON/Simulink models/DSSDK/SingleObject/TrackerObject.mexmaci64': dlopen(/Users/omarshadeed/Desktop/VICON/Simulink models/DSSDK/SingleObject/TrackerObject.mexmaci64, 6): Library not loaded: @executable_path/libViconDataStreamSDK_CPP.dylib Referenced from: /Users/omarshadeed/Desktop/VICON/Simulink models/DSSDK/SingleObject/TrackerObject.mexmaci64 Reason: image not found.