| Policies

Even thought Pyste can identify various elements in the C++ code, like virtual member functions, attributes, and so on, one thing that it can't do is to guess the semantics of functions that return pointers or references. In this case, the user must manually specify the policy. Policies are explained in the tutorial.

The policies in Pyste are named exactly as in Boost.Python, only the syntax is slightly different. For instance, this policy:

`

        return_internal_reference<1, with_custodian_and_ward<1, 2> >()

`

becomes in Pyste:

`

        return_internal_reference(1, with_custodian_and_ward(1, 2))

`

The user can specify policies for functions and virtual member functions with the `set_policy` function:

`

        set_policy(f, return_internal_reference())
        set_policy(C.foo, return_value_policy(manage_new_object))

`

What if a function or member function needs a policy and the user doesn't set one? If a function needs a policy and one was not set, Pyste will issue a error. The user should then go in the interface file and set the policy for it, otherwise the generated cpp won't compile.

Note that for functions that return `const T&`, the policy `return_value_policy<copy_const_reference>()` wil be used by default, because that's normally what you want. You can change it to something else if you need to, though.

Copyright © 2003 Bruno da Silva de Oliveira
Copyright © 2002-2003 Joel de Guzman
Permission to copy, use, modify, sell and distribute this document is granted provided this copyright notice appears in all copies. This document is provided "as is" without express or implied warranty, and with no claim as to its suitability for any purpose.