Re: creating a new type in C

I see, but aren't all those PG_GETARG_XXX functions supposed to do the
parsing and casting ? I though that's why they existed, to make the
manual parsing unnecessary and maybe eliminate bugs.

And another thought, is this the right query to insert data into this type ?
INSERT INTO pp values('(1, "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx")');

PS: this is a second reply, because the first time I forgot to CC to the
list, sorry.

On Fri, 18 Oct 2002, Gyorgy Molnar wrote:

> Hello,
> I think you gave the answer for your question by yourself. In the XXX_in
> function you have only one args. You have to parse it and covert it into the
> proper format by yourself.
>
> The sample code (complex type) very good in the Postgres docs
> http://www.postgresql.org/idocs/index.php?xtypes.html
>
> Complex *
> complex_in(char *str)
> {
> double x, y;
> Complex *result;
> if (sscanf(str, " ( %lf , %lf )", &x, &y) != 2) {
> elog(ERROR, "complex_in: error in parsing %s", str);
> return NULL;
> }
> result = (Complex *)palloc(sizeof(Complex));
> result->x = x;
> result->y = y;
> return (result);
> }
>
> It uses version 0 calling conversion in the sample, but the rest is the
> same.
>
> As you see the sscanf "C" library function is used to convert the argument
> string.
> In your case it is not going to work, becasue the sscanf in not good enough
> to make to conversion. The best way if you write a small function to make it
> for you.
>
> Best Regards,
> Yuri
>
>
>
> ----- Original Message -----
> From: "Andrei Ivanov" <andrei(dot)ivanov(at)ines(dot)ro>
> To: <pgsql-general(at)postgresql(dot)org>
> Sent: Friday, October 18, 2002 12:29 PM
> Subject: [GENERAL] creating a new type in C
>
>
> >
> > Hello,
> > I've been playing with a new type I want to create, but I got stuck,
> > therefore I ask for your assistance.
> > I don't know if this is the right list for this, if not please tell me
> > where to post my questions.
> > This is the source:
> >
> > #include "postgres.h"
> > #include "fmgr.h"
> >
> > typedef struct movie_property
> > {
> > int4 id;
> > char name[31];
> > } movie_property;
> >
> > Datum movie_property_in(PG_FUNCTION_ARGS);
> > Datum movie_property_out(PG_FUNCTION_ARGS);
> >
> > PG_FUNCTION_INFO_V1(movie_property_in)
> > Datum movie_property_in(PG_FUNCTION_ARGS)
> > {
> > int4 id = PG_GETARG_INT32(0);
> > char *name = PG_GETARG_CSTRING(1);
> > movie_property *result;
> > result = (movie_property *) palloc(sizeof(movie_property));
> > result->id = id;
> > strncpy(result->name, name, 30);
> > result->name[30] = 0;
> > PG_RETURN_POINTER(result);
> > }
> >
> > PG_FUNCTION_INFO_V1(movie_property_out)
> > Datum movie_property_out(PG_FUNCTION_ARGS)
> > {
> > movie_property *property = (movie_property *) PG_GETARG_POINTER(0);
> > char *result;
> >
> > if (property == NULL)
> > PG_RETURN_POINTER(NULL);
> > if ((result = (char *) palloc(40)) != NULL)
> > {
> > sprintf(result, "(%d,%s)", property->id, property->name);
> > }
> > PG_RETURN_CSTRING(result);
> > }
> >
> > Creating functions and type:
> > create function movie_property_in(opaque)
> > returns opaque
> > as '$libdir/movie_property'
> > language 'c';
> > create function movie_property_out(opaque)
> > returns opaque
> > as '$libdir/movie_property'
> > language 'c';
> > create type movie_property (
> > internallength = 35,
> > input = movie_property_in,
> > output = movie_property_out
> > );
> > CREATE TABLE pp (p movie_property);
> > INSERT INTO pp values('(1, "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx")');
> >
> > The problem is with movie_property_in function.
> > When I try to obtain the id with PG_GETARG_INT32(0),
> > I don't get 1, but 138944104.
> > I tried and logged the result of PG_GETARG_CSTRING(0), and it seems it
> > returns the whole string (1, "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx").
> > Please, tell me, how do I do this the right way ?
> > If you have any other comments regarding my code (I'm a C begginer),
> > they are welcomed.
> >
> > Postgresql version is 7.2.3 on a Gentoo Linux 1.2
> > gcc version 2.95.3 20010315
> >
> >
> >
> > ---------------------------(end of broadcast)---------------------------
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> >
> > http://www.postgresql.org/users-lounge/docs/faq.html
>
>