Why do I get "LNK1104: cannot open file 'ifmodintr.lib'" using "mex" with a Fortran file?

I am using MATLAB R2024a on a Windows machine to build and link a C++ MEX function to a Fortran object file. The "mex" function is using Microsoft Visual C++ 2022 as a compiler, and the Fortran object file was compiled using the Intel oneAPI 2024 for Fortran compiler.

When a run the "mex" function, I get the following error

>> mex myMexFunction.cpp myFortranObject.obj
Building with 'Microsoft Visual C++ 2022'.
Error using mex
LINK : fatal error LNK1104: cannot open file 'ifmodintr.lib'

How can I resolve this error?

Answer 1

[MathWorks Support Team]

The "ifmodintr.lib" library is provided by Intel. By default, "mex" is not configured to search for Intel's library files when using the Microsoft Visual C++ compiler.

To resolve this error, you must add the directory that contains the Fortran compiler's library files to the search path used by "mex". This can be done using the "-L" option, which is described in the following documentation page:

https://www.mathworks.com/help/matlab/ref/mex.html#btw17rw-1-option1optionN

For example, the default directory of the library files of the Intel oneAPI 2024 for Fortran compiler is 

C:\Program Files (x86)\Intel\oneAPI\compiler\2024.0\lib\

. So, your "mex" command would become:

mex("myMexFunction.cpp", "myFortranObject.obj", ...
    "-LC:\Program Files (x86)\Intel\oneAPI\compiler\2024.0\lib\");

For more information on insuring the compatibility of compilers used to build linked libraries and object files with the compiler used to build the "mex" function, see this article: https://www.mathworks.com/matlabcentral/answers/2123826-can-i-link-a-library-or-ojbect-file-built-with-one-compiler-to-a-mex-function-built-with-a-different