How do I work with variables from .mat files (mxArray) and pass them to Matlab functions in C++?

so I needed to read some variables from a .mat file using my C++ code, so I naturally used the C Matrix API (for example: `mat.h`) to get access to functions like `matOpen` or `matGetVariable` and it stores said variables in `mxArray` variables

Thing is, I need these said variables to use in my generated Matlab functions Matlab functions I compiled as C++ shared libraries and now use in C++.

However, these functions only accept `mwArray` not `mxArray` variables.

Is there a way around this?

There has to be, but I really can't see it atm, so any help would be highly appreciated!

Answer 1

[Eswaramoorthy]

Hi, From your question, I get to understand that, your finding a way to convert the 'mxArray' type variable to 'mwArary' type variable. There is a way to convert mxArray variables to mwArray variables so that you can use them in your C++ shared libraries.

To convert an mxArray variable to an mwArray variable, you can use the mwArray constructor that takes an mxArray argument. Here's an example:

#include "mat.h"
#include "matrix.h"

// Assume we have already opened the .mat file and read the variable into mxArray* variablePtr
// ...
    
mwArray mwVariable(variablePtr); // convert mxArray to mwArray

// Now we can use mwVariable in our C++ shared libraries

Note:

When you convert an mxArray to an mwArray, MATLAB creates a copy of the data. This means that if you modify the mwArray in your C++ code, the original mxArray will not be affected. If you need to modify the original data, you will need to copy the mwArray back to an mxArray when you're done.