Re: Looking for pure C function APIs for server extension: language handler and SPI

On Mon, Feb 29, 2016 at 5:55 PM, <david(at)andl(dot)org> wrote:

> What I need (to find or create) is a ‘pure’ C language API to support a
> Postgres server extension. By ‘pure’ I mean one that has no knowledge of
> Postgres internals and that could be called by a generic interface provided
> by some other tool that can support C language APIs.
>

​Well, since nobody else has replied yet, have you read:
http://www.postgresql.org/docs/9.5/interactive/libpq.html

libpq is the C callable API which communicates with the PostgreSQL server.
There is a "shared object" and a normal library which can be "statically
linked". But that's really all that _I_ know about it.
​

>
>
> The reason is that I’m looking to integrate a new language (*Andl*) into
> Postgres. To do that I need to find or create a ‘pure’ C-language API to
> interface with:
>
> 1. The generic language call interface (pl_language_handler), which
> must handle conversion of Incoming language call parameters and outgoing
> language call return value.
>
> 1. The backend query execution interface (SPI), which must handle
> conversion of outgoing query parameters and incoming query result values.
>
>
>
> There are 5 generic data types: boolean, binary (blob), number
> (decimal/real/integer), text (string/varchar), time (date/datetime). Each
> data type needs to be converted between the Postgres internal data types (
> Datum) and some intermediate data type that can be passed through a pure
> C API. In my case that will be C# (MS or Mono), but others might want to
> use Java or whatever.
>
>
>
> These conversion tasks are identical to those needed to implement an
> ODBC/JDBC or similar interface, but one bound directly to the server and
> not going through a client (socket) connection. I have already done this
> successfully with Sqlite, which already provides a pure C server API and
> excellent documentation to go with it, so I know what it might look like.
>
>
>
> FYI apart from these two APIs (and their 4x5 conversions), the only other
> thing needed is some SQL code generation and I expect to have a working
> language of considerable power.
>
>
>
> Any help, suggestions, pointers much appreciated.
>
>
>
> Regards
>
> David M Bennett FACS
> *------------------------------*
>
> *Andl - A New Database Language - andl.org <http://andl.org>*
>
>
>

--
The man has the intellect of a lobotomized turtle.

Maranatha! <><
John McKown