Thread

1. RE: Strangeness/bug when working with my own datatype in P ostgreSQL

   KS <ks@tcnet.ru> — 2001-02-26T10:58:32Z

   Hello, Tom.
   
   I tried to reproduce the situation from the very beginning (created a new
   DB, created the datatype in it) but the effect did not reproduce.
   I continued the investigation and found that it is just suffictient to
   re-create a datatype in an existing DB for the effect to disappear.
   Thus, I think that the reason was in some accidental combination of
   circumstances.
   Unfortunately, I cannot recall the order of my actions, which lead to this
   strange situation.
   But I still feel curious about this fact.
   If you also do, and if you think that my sources can help you in analyzing
   the situation, here is the code I used to build my datatype:
   
   1. Here's the code of the four "C" functions, used serve my "int1" datatype:
   
   ------------------------8<------------------------
   #include "postgres.h"
   #include <stdio.h>
   
   typedef unsigned char int1;
   
   // IN - OUT functions
   int1	*int1_in(char *str);
   char	*int1_out(int1 *i);
   
   // Convertion functions
   int1	*i4toi1(int4 i);
   int4	i1toi4(int1 *i);
   
   /***************************************************************************
   **
    * Input/Output functions
    
   ****************************************************************************
   */
   
   int1	*int1_in(char *str)
   {
    unsigned int i;
    int1 *result;
    if ( sscanf( str, "%u", &i ) != 1 )
    {
     elog(ERROR, "int1_in: error in parsing \"%s\"", str);
     return NULL;
    }
    if ( ( i < 0 ) || ( i > 255 ) )
    {
     elog(ERROR, "int1_in: error in parsing \"%s\"", str);
     return NULL;
    }
    result = (int1*)palloc(sizeof(int1));
    (*result) = i;
    return result;
   }
   
   char *int1_out(int1 * i)
   {
    char *result;
    if ( i == NULL ) return NULL;
    result = (char *) palloc( 60);
    sprintf(result, "%u", (*i));
    return result;
   }
   
   /***************************************************************************
   **
    * Type conversion functions
    
   ****************************************************************************
   */
   
   int1	*i4toi1(int4 i)
   {
    int1 *result;
    if ( ( i < 0 ) || ( i > 255 ) )
    {
     elog(ERROR, "i4toi1: %d is out of bounds (0...255)", i);
     return NULL;
    }
    result = (int1*)palloc(sizeof(int1));
    (*result) = i;
    return result;
   }
   
   int4	i1toi4(int1 *i)
   {
    return (*i);
   }
   ------------------------8<------------------------
   
   2. That's how I built the library:
   cc -I /usr/local/pgsql/include -I /usr/local/include -fpic -DPIC -shared -o
   int1.so int1.c
   
   3. Here are the sql statements I used to create the datatype:
   create function int1_in(opaque) returns int1 as
   '/usr/local/pgsql/data/int1.so' language 'C';
   create function int1_out(opaque) returns opaque as
   '/usr/local/pgsql/data/int1.so' language 'C';
   create type int1 ( input = int1_in, output = int1_out, internallength = 1,
   externallength = 3, default = "" );
   create function int1(int4) returns int1 as '/usr/local/pgsql/data/int1.so',
   'i4toi1' language 'C';
   create function int4(int1) returns int4 as '/usr/local/pgsql/data/int1.so',
   'i1toi4' language 'C';
   
   Hope, this will help you.
   
   Best Regards, 
   Konstantin Solodovnikov.
   
   > -----Original Message-----
   > From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
   > To: Солодовников Константин
   > Subject: Re: [BUGS] Strangeness/bug when working with my own datatype in
   PostgreSQL 
   > 
   > > When I insert a new row into this table without providing a 
   > value for the
   > > "i1" column, I get a value of "45" in it.
   > 
   > Seems odd to me too; it should default to NULL if no value is 
   > specified
   > or available from a DEFAULT clause.  Can't guess why you're seeing a
   > problem without more details, though.  Could you show us the code you
   > used to define your datatype?
   > 
   > 			regards, tom lane
   > 
   
   

2. Re: Strangeness/bug when working with my own datatype in P ostgreSQL

   Tom Lane <tgl@sss.pgh.pa.us> — 2001-02-26T15:37:04Z

   =?KOI8-R?Q?=F3=CF=CC=CF=C4=CF=D7=CE=C9=CB=CF=D7_=EB=CF=CE=D3=D4=C1?= =?KOI8-R?Q?=CE=D4=C9=CE?= <ks@tcnet.ru> writes:
   > create type int1 ( input = int1_in, output = int1_out, internallength = 1,
   > externallength = 3, default = "" );
   
   I'm not sure what it will do to specify a default value for a type that
   is not a legal value of the datatype --- but it can't be good.  Take out
   the default clause.
   
   It also seems a tad bizarre to be treating int1 as a pass-by-reference
   datatype, but that's probably not causing any misbehavior, just
   inefficiency...
   
   			regards, tom lane