Обсуждение: 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

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