38.10.6. Composite-Type Arguments C-language function code demo works for int, but not for numeric.

[jian he <jian.universality@xxxxxxxxx>]

Hi.

source: https://www.postgresql.org/docs/current/xfunc-c.html#XFUNC-C-BASETYPE (38.10.6. Composite-Type Arguments)

column "salary" int data type works fine. But it does not work if the "salary" column data type is numeric.

/*
rm funcs.so && rm funcs.o
gcc -I/home/jian/postgres/pg16/include/postgresql/server -fPIC -c funcs.c
gcc -shared -o funcs.so funcs.o
*/

#include "postgres.h"
#include "executor/executor.h"
#include  "utils/numeric.h"

PG_MODULE_MAGIC;

PG_FUNCTION_INFO_V1(c_overaid);

Datum
c_overaid(PG_FUNCTION_ARGS)
{
    HeapTupleHeader t = PG_GETARG_HEAPTUPLEHEADER(0);
    Numeric           limit = PG_GETARG_NUMERIC_COPY(1);
    bool isnull;
    Datum   salary;

    salary = GetAttributeByName(t,"salary",&isnull);
    if(isnull)
        PG_RETURN_BOOL(false);

    /* alternatively, we might prefer to do PG_RETURN_NULL() for null salary */
    PG_RETURN_BOOL(DatumGetNumericCopy(salary) > limit);
}
---------------------------------------------------------------------------

then quit the session and reconnect the session.

drop table emp cascade;
create table emp(empid bigint, salary numeric, name text);
insert into emp values(1,1000,'a1');
insert into emp values(2,1100,'a2');
insert into emp values(3,1200,'a3');
CREATE OR REPLACE FUNCTION c_overaid(emp, numeric) returns boolean AS '/home/jian/pg_ext/misc/funcs','c_overaid' LANGUAGE C STRICT;
select name, c_overaid(emp,numeric '1110') as over_paid from emp;

it returns

 name | over_paid
------+-----------
 a1   | t
 a2   | t
 a3   | t
(3 rows)

I also tried PG_GETARG_NUMERIC,DatumGetNumeric(salary).