How to throw an exception when using MATLAB C or C++ API

I have a C++ code, which is like:

mexFunction(int nlhs, mxArray  *plhs[], int  nrhs, const mxArray *prhs[])
{
   try{
    // Here is my code
    }catch(...){
        mexErrMsgTxt("Something Wrong");
    }

}

After mex the code, I want to get "Something Wrong" in MTALAB window if any exception was throwed from the "try" part.

However, if there do some errors in the code (inside the try curly bracket), it will crush my MATLAB like

The try-catch seems ineffective in this stuation. So how to throw an exception from C++ to MATLAB if anything wrong?

Answer 1

[Aiswarya]

Hi,

I understand that you are trying to throw an exception from C++ to MATLAB after converting the code to a MEX function.

The try-catch method results in a MATLAB crash. However, you can use the mexErrMsgIdAndTxt function : https://www.mathworks.com/help/matlab/apiref/mexerrmsgidandtxt.html?searchHighlight=mexErrMsgIdAndTxt&s_tid=srchtitle_support_results_1_mexErrMsgIdAndTxt&s_tid=mwa_osa_a

This displays the error in the MATLAB command window.

You may refer to a C++ example code (mexcpp.cpp) which implements error handling by running the following command in the MATLAB Command Window:

edit([matlabroot '/extern/examples/mex/mexcpp.cpp']);

[Ziyu Hua]

Thanks, I re-compile the code below like this and it seems to be fine.

#include"mex.h"
void mexFunction(int nlhs, mxArray* plhs[], int nrhs, const mxArray* prhs[])
{
        try {
            // Here is my code
            throw(1);
        }
        catch (...) {
            mexErrMsgIdAndTxt("error","Something Wrong");
        }
}

The output of the MATLAB is an error message.

I can't remember what particular problems I once met, but it seems that they have been resolved.

Thanks.