C-MEX file: I want to return an empty array, does anyone know how?

If I assign plhs[0] = NULL; I get a warning in Matlab's command window and the output argument is not created/modified. Any attempt to create a matrix or an array with 0's dimensions causes Matlab to crash.

Answer 1

[James Tursa]

This will return an empty 0x0 matrix:

#include "mex.h"
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
    plhs[0] = mxCreateDoubleMatrix( 0, 0, mxREAL );
}

If you need something else please provide more detail about what you are trying to do.

[Mayela]

Thanks, James. It works. Best wishes, Mayela

Answer 2

[Vincent Huber]

In C++ if I call for

value = feval(mh,"myMexfunction",arg1,...)

with inside

outputs[0] = factory.createArray<double>({ 0,0 });

Matlab complains the following way:

Error using matlab.mex.MexHost/feval
Too many output arguments.