Re: How to retrieve values of 'array' field using C library (libpq)

Hi.

I use libpq in my program. And I can retrieve int and symbolic fields
as simple as

int unameFN, moneyFN...
char *unamePTR, *moneyPTR...

unameFN = PQfnumber(res, "uname");
moneyFN = PQfnumber(res, "money");
unamePTR = PQgetvalue(res, 0, unameFN);
moneyPTR = PQgetvalue(res, 0, moneyFN);
themoney = ntohl(*((uint32_t *) moneyPTR));
printf("user->[uname:%s money:%d]", unamePTR, themoney);

Then I tried to use array type and no success:

int arFN...
char *arPTR...

arN = PQfnumber(res, "woo");
arPTR = PQgetvalue(res, 0, arFN);
printf("user->[woo:%s]", arPTR);

I can convert it with array_to_string() and got it as some text.

My array is the array of integer values. So maybe there is some native
method to retrieve them (as in the 'themoney' example)?
--
antonvm

Hey Anton,

2011/2/9 Anton Maksimenkov <anton200(at)gmail(dot)com>

> Hi.
>
> I use libpq in my program. And I can retrieve int and symbolic fields
> as simple as
>
>
> int unameFN, moneyFN...
> char *unamePTR, *moneyPTR...
>
> unameFN = PQfnumber(res, "uname");
> moneyFN = PQfnumber(res, "money");
> unamePTR = PQgetvalue(res, 0, unameFN);
> moneyPTR = PQgetvalue(res, 0, moneyFN);
> themoney = ntohl(*((uint32_t *) moneyPTR));
> printf("user->[uname:%s money:%d]", unamePTR, themoney);
>
>
> Then I tried to use array type and no success:
>
> int arFN...
> char *arPTR...
>
> arN = PQfnumber(res, "woo");
> arPTR = PQgetvalue(res, 0, arFN);
> printf("user->[woo:%s]", arPTR);
>
> I can convert it with array_to_string() and got it as some text.
>
> My array is the array of integer values. So maybe there is some native
> method to retrieve them (as in the 'themoney' example)?
>
Not in libpq. Probably, in libpqtypes.

> --
> antonvm
>
> --
> Sent via pgsql-general mailing list (pgsql-general(at)postgresql(dot)org)
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-general
>

--
// Dmitriy.

On Wed, Feb 09, 2011 at 02:53:37PM +0300, Dmitriy Igrishin wrote:
> > My array is the array of integer values. So maybe there is some native
> > method to retrieve them (as in the 'themoney' example)?
> >
> Not in libpq. Probably, in libpqtypes.

I ended up writing one for pgsnmpd, which you're welcome to use. I can't
guarantee that writing my own was the best way to do it, or that it's free of
bugs. See pg_array.c and pg_array.h at
http://git.postgresql.org/gitweb?p=pgsnmpd.git;a=summary

--
Joshua Tolley / eggyknap
End Point Corporation
http://www.endpoint.com