Troubleshooting MEX API Incompatibilities

File Is Not A MEX File

For more information, see MEX Platform Compatibility.

MEX File Compiled With Incompatible Options

When you build object files into a MEX function, make sure they are built with the same version of the C or Fortran Matrix API.

This error occurs when you compile two or more files independently with the -c compile-only option, then try to build them into a MEX function. For example:

mex -c function1.c -largeArrayDims
mex -c function2.c -R2018a
mex function1.o function2.o

MEX File Compiled With One API And Linked With Another

This error occurs when you compile a file with the -c compile-only option and then link with a version of the API that is incompatible. For example, if you use the following commands to build a MEX file, then the function errors at runtime.

mex -c function1.c -largeArrayDims
mex function1.o -R2018a

C++ MEX File Using MATLAB Data Array API Compiled With Incompatible Option

If you create a C++ MEX file using functions in the MATLAB Data API for C++, then the following build command errors.

mex function.cpp -R2017b

Use this command instead.

mex function.cpp

Custom-built MEX File Not Supported In Current Release

MATLAB^® does not find a version number in the MEX file. The MEX file uses functions in an API that requires a version number. For more information, see https://www.mathworks.com/matlabcentral/answers/377799-compiling-mex-files-without-the-mex-command.

MEX File Is Compiled With Outdated Option

Your source code is compatible with the interleaved complex API. For best results, replace the mex -largeArrayDims build option with the -R2018a option.