[C++-sig] How to specify a double return type?

Ralf W. Grosse-Kunstleve rwgk at yahoo.com
Mon Mar 22 15:54:09 CET 2004

Is dReal a typedef for double or float? If so: Python float are immutable. You
cannot return pointers to immutable types. Somehow you have to change your
interface, e.g. through the use of "thin wrappers."
Please explain in more detail what exactly you want to do; hopefully this will
lead us to the best solution.

--- brett hartshorn <bhartsho at yahoo.com> wrote:
> I have a type called dReal, that can either be a float or double number type,
> depending on the
> build options.  A member function in my class returns a dReal type, this is
> giving me problems in
> Boost.  I am still new to boost, so i am not sure what to do.  
> Here is the error i get:
> /usr/include/boost/python/detail/invoke.hpp:93: error: no match for call to
> `(
>    dReal*>) (const dReal*)'
> I've tried to use:
>    return_internal_reference<>()
>    return_value_policy<manage_new_object>())
>    return_value_policy<reference_existing_object>()
> but to no avail.
> Also i have member functions that take in a dReal number.  What is the best
> way to pass that
> function a dReal type?  Or can i just pass floats and doubles in python and
> boost will treat those
> as a dReal?

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