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