[C++-sig] (Nat Goodspeed) pass function pointerto c

[Stefan Seefeld]

Qinfeng(Javen) Shi wrote:
> Hi Nat,
> 
> Thank you very much.
> I tried what you said, but it seems boost::python::object can't be
> converted to float by (float) (op(a,b)).  So I converted the pointer of
> op's result into float*, but got a unexpected result. Something wrong
> with my code?
> 
> -------------------------c extension---------------
> boost::python::object op;
> 
> void process(arg1,..., boost::python::object arg_op){
>    ...
>    op = arg_op;
>    ...
>    float a = 1;
>    float b = 2;
> 
>    boost::python::object rlt = op(a,b);
>    float * f = (float *) (rlt.ptr());

make that

float f = boost::python::extract<float>(rlt);

Would that work ?

On a stylistic note:
There is almost never a reason to use C-style casts
in a C++ program. At least use one of const_cast, static_cast,
or reinterpret_cast instead.

HTH,
		Stefan

-- 

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