Re: help defining a basic type operator

On Mon, Aug 20, 2018 at 4:51 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> Luca Ferrari <fluca1978(at)gmail(dot)com> writes:
> > I'm trying to define a custom data type that would represent a number
> > of bytes in a lossy human way.
>
> You did not show us the SQL definition of the type. I don't see anything
> obviously wrong in what you showed (other than hfsize_add not setting the
> result's scaling), so the problem is somewhere else. Given this C
> declaration, the type probably needs to be size 16, double alignment,
> pass-by-reference; maybe you messed up part of that?
>

Shame on me: when I issued a create type I didn't realize that I was
miswriting the length attribute from 'internallength' to
'internalsize', and while an error was reported, the type was created.
Fixing the type creation into:

CREATE TYPE hfsize (
internallength = 16,
input = hfsize_input_function,
output = hfsize_output_function
);

solved the problem, so it was a length mismatch.

> > HFSize *sum = new_HFSize();
>
> What is new_HFSize?

An helper function to allocate a new object (and that was why scaling
did not get referenced in the add function):

HFSize*
new_HFSize()
{
HFSize *size = (HFSize*) palloc( sizeof( HFSize ) );
size->scaling = 0;
size->size = 0.0f;
return size;
}

Thanks,
Luca