Re: libpq and Datums management with embedded C function

I see that dblink is 2500 lines more or less...
Is there anyone how to set up correctly the 2 lines I posted before?

I will explore SPI anyway hoping it will gett my life easier...

> On Thu, Feb 17, 2011 at 4:16 AM, Alessandro Candini<candini@meeo.it>  wrote:
>> I'm dealing witch a C function embedded into postgresql-9.0.2.
>>
>> I'm returning a set of rows and following the example here
>> http://www.postgresql.org/docs/9.0/static/xfunc-c.html everything works
>> fine, but only if I use the C string approach.
>>
>> I'm using libpq to retrieve data and something like this works fine:
>> snprintf(values[0], 16, "%s", PQgetvalue(funcctx->user_fctx, call_cntr, 0));
>> because PQgetvalue returns an array of char.
>>
>> But if I want to get the original data as output, I have to deal with Datums
>> and I don't know how to do this with lippq.
>> Something like the following it doesn't work:
>>
>> Datum values[1];
>> values[0] = (Datum) PQgetvalue(funcctx->user_fctx, call_cntr, 1);
>> snprintf(values[0], 16, "%s", PQgetvalue(funcctx->user_fctx, call_cntr, 0));
>>
>> Have you got any idea of how to solve this...do you know another way to
>> perform a query indide the db without involve libpq?
>> I would prefer to use them because I can connect to several postgresql
>> instances.
> Have you ruled out dblink?  Also for connecting to self it would be
> preferable to use SPI
> (http://www.postgresql.org/docs/9.0/static/spi.html) vs libpq.
>
> merlin


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Alessandro Candini

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