Question

I use C++ and swig to do some calculations. To simplify it, lets assume it looks like this:

struct TestIt{
  TestIt(float x):x(x){};
  inline float& getIt() {return x;};
  float x;
};

Now I want to use the the getIt() function and print the float value.

With

testee = matching.TestIt(42)
print(testee.getIt())

I get

<Swig Object of type 'float *' at 0x1cb1690>

which makes sense, because getIt returns a reference. How can I dereference it/get a python float out of it (without changing the c++ code)?

Answer 1

Have a look here and here. You’d write something like this in your SWIG module:

%pointer_class(float, floatp)

That will let you do this in your Python code:

print(testee.getIt().value())

You will need to change your SWIG module, or write one if you are swigging the C++ header file directly. But you can probably get away with simply including your C++ header from there.