Overriding compiler switch in MEX

Hello,

I am using MATLAB 2019a and trying to create a MEX file from Fortran code.

My Fortran compiler is 'Intel Parallel Studio XE 2019 for Fortran with Microsoft Visual Studio 2017'.

The MEX configuration has a default compiler switch /integer-size:64. However, I have some legacy Fortran code, where integers are not explicitly declared, and I don't want these to be taken as 64-bit integers. So, I try to override this by

mex -v COMPFLAGS='$COMPFLAGS /integer-size:32' -largeArrayDims filename

But this results in the command line

ifort /c /nologo /fpp /Qprec /MD /fp:source /assume:bscc -I"C:\Program Files\MATLAB\R2019a\extern\include" /DMX_COMPAT_64 /DMATLAB_DEFAULT_RELEASE=R2017b /DUSE_MEX_CMD /DMATLAB_MEX_FILE /integer-size:32 /integer-size:64 /O2 /DNDEBUG filename

where somehow the compiler switch /integer-size:64 gets stuck in after my switch, and I get the warning,

ifort: command line warning #10121: overriding '/integer-size:32' with '/integer-size:64'

I am not finding the /integer-size switch in my mex_FORTRAN_win64.xml file, and I don't know what is causing it to get appended.

Any advise on how I could stop that switch from getting appended to the commandline, or how I could override it?

Thank you.

Siva

[Walter Roberson]

On Mac, there is a switch generated automatically that is incompatible with gfortran. I ended up having to write a some filter code named after the compiler that removed the option and then passed the rest of the command line to the real gfortran compiler.

[James Tursa]

Sigh ... TMW should have never put that switch in there in the first place, for this very reason. Better to let the users decide for themselves what they want default integers to be.

[Siva]

Thank you Walter and James for your input.

I made a batch file with the compile and link command lines, with the proper switches, and ran it in the Intel Fortran console in Windows (where paths and environment variables have been appropriately set).

This seems to work. I will probably write a makefile, and I am hoping this will work for my purposes now.

It will still be better if some configuration can be changed, so that I can execute mex from the MATLAB environment.

[dpb]

TMW has made such a mess of mex by trying to be too clever by half. :(

They should just tell folks how to compile and have a simple batch file that is user-accessible AND FULLY DOCUMENTED.

[James Tursa]

I guess one improvement is that I don't see the /fixed option anymore. Did TMW finally get rid of it?

[Siva]

I was able to remove the /fixed switch in the configuration file.

[James Tursa]

Oh, you did that one yourself. Guess I was hoping for too much ...

[dpb]

Hope is about all there is for TMW ever doing anything really useful with the mex interface it seems...

I railed at them extensively 20+ years ago and all fell on totally deaf and apparently completely disinterested ears...

Answer 1

[Siva]

This is what I ended up doing.

1. Following https://www.mathworks.com/help/matlab/matlab_external/using-mex-script-options-to-custom-build.html, mex -v -n filename
2. Get the list of command lines
3. Make a batch file or makefile, adding/deleting compiler switches

Although not as convenient as simply being able to use mex in the MATLAB environment, this seems to give the necessary flexibility. Perhaps this is the intention of Mathworks.

This is simple enough, but just wanted to post it as an accepted answer to close this question.

Thank you all for your input.

Siva