Defining the Structure Type (KEY Field)

To include a separate structure type definition for the KEY fields in a format, specify the KEY option on the #pragma mapinc directive. Comments are listed beside the fields in the structure definition to indicate how the key fields are defined in the externally described file.

C++ language onlyC++ users must use the GENCSRC utility for structure type definition.

C language onlyC users can use either the GENCSRC utility or the #pragma mapinc directive for structure type definition.

Note: For more information on the differences between the GENCSRC utility and the #pragma mapinc directive, see The GENCSRC Utility and the #pragma mapinc Directive.

Example:

The following ILE C program contains the #pragma mapinc directive to include the externally described database file CUSMSTL: 
 
#pragma mapinc("custmf","example/cusmstl(cusrec)","both key","d")
#include "custmf"
The following example contains the DDS for the file T1520DD8 in the library MYLIB.
Figure 1. T1520DD8 — DDS Source for Customer Records
A* CUSTOMER MASTER FILE -- T1520DD8
     A          R CUSREC                    TEXT('Customer master record')
     A            CUST           5          TEXT('Customer number')
     A            NAME          20          TEXT('Customer name')
     A            ADDR          20          TEXT('Customer address')
     A            CITY          20          TEXT('Customer city')
     A            STATE          2          TEXT('State abbreviation')
     A            ZIP            5  0       TEXT('Zip code')
     A            ARBAL         10  2       TEXT('Accounts receivable balance')
     A          K CUST
     A*
     A*
Program T1520EDF uses the #pragma mapinc directive to generate the file field structure that is defined in T1520DD8.
Figure 2. T1520EDF — ILE C Source to Include an Externally Described Database File
/* This program contains the #pragma mapinc directive to              */
/* include the externally described database file T1520DD8.           */
/* This program reads customer information from a terminal and issues */
/* a warning message if the customer's balance is less than $1000.    */
 
#include <stdio.h>
#include <recio.h>
#include <stdlib.h>
#include <string.h>
#include <decimal.h>
 
#pragma mapinc("custmf","QGPL/T1520DD8(cusrec)","both key","_P")
#include "custmf"
 
 
int main(void)
{
 
 /* Declare x of data structure type QGPL_T1520DD8_CUSREC_both_t.     */
 /* The data structure type was defined from the DDS specified.       */
 
 QGPL_T1520DD8_CUSREC_both_t x;
 
 /* Get information from entry.                                       */
 
 printf("Please type in the customer name (max 20 char).\n");
 gets(x.NAME);
 printf("Please type in the customer balance.\n");
 scanf("%D(10,2)",&x.ARBAL);
 
 /* Prints out warning message if x.ARBAL<1000.                       */
 
 if (x.ARBAL<1000)
 
 {
  printf("%s has a balance less than $1000!\n", x.NAME);
 }
 
}

The type definitions are created in your ILE C source listing that is based on the #pragma directive that is specified in the ILE C source program.

The output is as follows: 
   Please type in the customer name (max 20 char).
 > James Smith
   Please type in the customer balance.
 > 250.58
   James Smith has a balance less than $1000!
   Press ENTER to end terminal session.
The DDS part of the program listing is as follows:
Figure 3. Ouput Listing from Program T1520EDF — Customer Master Record
/* ------------------------------------------------------------------------*/
/* PHYSICAL FILE: QGPL/T1520DD8                                           */
/* FILE CREATION DATE: 93/08/14                                            */
/* RECORD FORMAT: CUSREC                                                   */
/* FORMAT LEVEL IDENTIFIER: 4E9D9ACA60E00                                  */
/* ------------------------------------------------------------------------*/
typedef _Packed struct {
   char CUST[5];                     /*  Customer number   */
   char NAME[20];                    /*  Customer name     */
   char ADDR[20];                    /*  Customer address  */
   char CITY[20];                    /*  Customer city     */
   char STATE[2];                    /*  State abbreviation*/
   decimal(5,0) ZIP;                   /*  Zip code                 */
                                       /*  PACKED SPECIFIED IN DDS    */
   decimal(10,2) ARBAL;                /*  Accounts receivable balance*/
                                       /*  PACKED SPECIFIED IN DDS   */
}QGPL_T1520DD8_CUSREC_both_t;
typedef _Packed struct {
   char CUST[5];
                                        /*  DDS - ASCENDING*/
                                        /*  STRING KEY FIELD*/
}QGPL_T1520DD8_CUSREC_key_t;