sql3types.h does not include "BigInt"

[Niko Ware <nikowareinc@xxxxxxxxx>]

I'm using "dynamic sql" to process generic queries (see code fragment below). The routine works correctly for most data types, but it does not work for functions (e.g., NextVal()). The data TYPE returned for NextVal() sequence is zero (see line 24 of the code fragment). The documented data type for NextVal() is "bigint" (see https://www.postgresql.org/docs/current/functions-sequence.html). The query being executed is "SELECT NEXTVAL('my_sequence')".

The data types defined in sql3types.h (see below) do not include "zero" or "bigint" (the enumerated values start at "1"). My function defaults the data type to "String" which returns a NULL terminated character array with the expected value. I'm able to coerce this to an integer at the application level, but there are other "unknown" cases where my application is requesting the result of a function. The application code does not always coerce the value to the correct type (it assumes the type based on the query) which results in unexpected operations.

How do I identify these "out of bound" data types and properly coerce them to the expected type? At a minimum I would like to handle the results from sequence manipulation functions. Is there an alternate descriptor field which can be used to identify the function return type (bigint) so that it can be properly cast?

-------------------------------------------------

SQL3TYPES.H

/* SQL3 dynamic type codes */
/* chapter 13.1 table 2: Codes used for SQL data types in Dynamic SQL */

enum
{
   SQL3_CHARACTER = 1,
   SQL3_NUMERIC,
   SQL3_DECIMAL,
   SQL3_INTEGER,
   SQL3_SMALLINT,
   SQL3_FLOAT,
   SQL3_REAL,
   SQL3_DOUBLE_PRECISION,
   SQL3_DATE_TIME_TIMESTAMP,
   SQL3_INTERVAL,          /* 10 */
   SQL3_CHARACTER_VARYING = 12,
   SQL3_ENUMERATED,
   SQL3_BIT,
   SQL3_BIT_VARYING,
   SQL3_BOOLEAN,
   SQL3_abstract
   /* the rest is xLOB stuff */
};

-------------------------------------------------

CODE FRAGMENT:

  1    EXEC SQL WHENEVER SQLERROR GOTO myErrorHandler;
  2    EXEC SQL WHENEVER NOT FOUND DO break;
  3
  4    EXEC SQL ALLOCATE DESCRIPTOR my_desc;
  5
  6    EXEC SQL PREPARE my_prepare FROM :my_sql_query;
  7    EXEC SQL DECLARE my_cursor CURSOR FOR my_prepare;
  8    EXEC SQL OPEN my_cursor;
  9
 10    while (TRUE)
 11    {
 12       EXEC SQL FETCH NEXT FROM my_cursor INTO SQL DESCRIPTOR my_desc;
 13
 14       if (gdat->cols == NULL)
 15       {
 16          EXEC SQL GET DESCRIPTOR my_desc :my_num_cols = COUNT;
 17
 18          if ((gdat->num_cols = my_num_cols) > 0)
 19          {
 20             if ((gdat->cols = (ColDat*) calloc(gdat->num_cols, sizeof(ColDat))) != NULL)
 21             {
 22                for (my_col = 1; my_col <= gdat->num_cols; my_col++)
 23                {
 24                   EXEC SQL GET DESCRIPTOR my_desc VALUE :my_col :my_name = NAME, :my_type = TYPE;
 25                   OAStrCpySize(gdat->cols[my_col-1].name, my_name.arr);
 26                   gdat->cols[my_col-1].type = GDconvertSQL13Type(my_type);
 27                   OAprintf("----- %d = %d\n", gdat->cols[my_col-1].type, my_type); //~~
 28                }
 29             }
 30          }
 31       }
 32    }