C++ compilation error

Dear all,

Why am I getting this error when I compile using mex. when I compile using Xcode 'clang++' everything is fine.

******************************

#include <iostream>

#include "mex.hpp"

#include "mexAdapter.hpp"

using namespace std;

using namespace matlab::data;

using matlab::mex::ArgumentList;

class Z {

public:

      void get (){
          cin>> x;
      }
      void print (){
          cout<<"the integer:" << x;
      }
  private:
      int x;
  };

class MexFunction : public matlab::mex::Function {

      Z abd;
      abd.get();
      abd.print();
   };

***************************************error*************>> 

mex -setup C++

MEX configured to use 'Xcode Clang++' for C++ language compilation.
Warning: The MATLAB C and Fortran API has changed to support MATLAB
   variables with more than 2^32-1 elements. You will be required
   to update your code to utilize the new API.
   You can find more information about this at:
   https://www.mathworks.com/help/matlab/matlab_external/upgrading-mex-files-to-use-64-bit-api.html.

>> mex maher1.cpp
Building with 'Xcode Clang++'.

Error using mex
/Users/maherheal/Dropbox/maherphd/1UK/Last/Code_v3/maher1.cpp:22:5: error: unknown type name 'abd'
    abd.get();
    ^
/Users/maherheal/Dropbox/maherphd/1UK/Last/Code_v3/maher1.cpp:22:8: error: expected member name or ';'
after declaration specifiers
    abd.get();
    ~~~^
/Users/maherheal/Dropbox/maherphd/1UK/Last/Code_v3/maher1.cpp:23:5: error: unknown type name 'abd'
    abd.print();
    ^
/Users/maherheal/Dropbox/maherphd/1UK/Last/Code_v3/maher1.cpp:23:8: error: expected member name or ';'
after declaration specifiers
    abd.print();
    ~~~^
4 errors generated.

Answer 1

[Viggnesh Venkatakrishnan]

Hi Maher,

I understand that you are having a problem with compiling the given code using MEX. I tried reproducing the issue at my end and observed the following:

class MexFunction : public matlab::mex::Function {
      Z abd;
      abd.get();
      abd.print();
   }; 

In the above part of the code MexFuntion is a class which has an object of the class Z as one of the data members. The next line of the code calls the member funtion of class Z using the same object that was created. C++ does not allow a funtion/Method call directly inside a class. You can do it in the following way instead:

   class MexFunction : public matlab::mex::Function {
      Z abd;
      MexFuntion()
      {
          abd.get();
          abd.print();
      }
   };  

In the above code snippet, the Method of class Z is being called after the Data member abd has been constructed.

If you can any specific questions regarding c++ mex please refer to the example given in the doc :https://www.mathworks.com/help/matlab/matlab_external/c-class-in-mex-files.html

Thank you ,

Viggnesh Venkatakrishnan

[Maher]

Thank you very much!

[Walter Roberson]

Is MexFuntion() a typing mistake ? Should it be MexFunction() ?