Class of array
Numeric identifier of the class (category) of the mxArray that pm points to. For a list of C-language class identifiers, see the mxClassID reference page.
Use mxGetClassId to determine the class of an mxArray. The class of an mxArray identifies the kind of data the mxArray is holding. For example, if pm points to a logical mxArray, then mxGetClassId returns mxLOGICAL_CLASS (in C).
mxGetClassId is like mxGetClassName, except that the former returns the class as an integer identifier and the latter returns the class as a string.
See the following examples in matlabroot/extern/examples/mex.
See the following examples in matlabroot/extern/examples/refbook.