Please explain what are these warning by SWIG and how to avoid it?

```
Warning 503: Can't wrap 'operator ()' unless renamed to a valid identifier.
Warning 503: Can't wrap 'operator =' unless renamed to a valid identifier.
Warning 503: Can't wrap 'operator *' unless renamed to a valid identifier.

```

The warnings are generated when SWIG generated C++ code is compiled under Android NDK.