Unable to retrieve data area value using QXXRTVDA and brace-initialized values - c

Question

I was trying to do simple data area value retrieval using C source from here:
https://www.ibm.com/support/knowledgecenter/en/ssw_ibm_i_71/rtref/qxxrtvd.htm
And... the code failed to do certain retrieval.
Here is the code:
typedef struct _DTAA_NAME_T {
char dtaa_name[10]; /* name of data area */
char dtaa_lib[10]; /* library that contains data area */
}_DTAA_NAME_T;
and
#include <stdio.h>
#include <xxdtaa.h>
#define DATA_AREA_LENGTH 30
#define START 6
#define LENGTH 7
int main(void)
{
char uda_area[DATA_AREA_LENGTH];
/* Retrieve data from user-defined data area currently in MYLIB */
_DTAA_NAME_T dtaname = {"USRDDA ", "MYLIB "};
/* Use the function to retrieve some data into uda_area. */
QXXRTVDA(dtaname,START,LENGTH,uda_area);
/* Print the contents of the retrieved subset. */
printf("uda_area contains %7.7s\n",uda_area);
}
There are several problems in this brace-intialized values:
_DTAA_NAME_T dtaname = {"USRDDA ", "MYLIB "};
Values can not get initialized with 10 characters value - only 9 chars + null byte.
Initializing values with 10 characters will lead to compilation error.
Initializing it with anything less than 10 characters will lead to null byte appending thus the QXXRTVDA will not find any values as soon as there's no such library with null byte ending.

Answer 1

The workaround I've found is to avoid brace-initialization and initialize values with direct bytes copying:
#include <stdio.h>
#include <xxdtaa.h>
#include <QSYSINC/MIH/CPYBLA>
#define DATA_AREA_LENGTH 30
#define START 6
#define LENGTH 7
int main(void)
{
char uda_area[DATA_AREA_LENGTH];
_DTAA_NAME_T dtaara;
memset( &dtaara, ' ', sizeof(dtaara));
cpybla( dtaara.dtaa_name, "USRDDA", 6);
cpybla( dtaara.dtaa_lib, "MYLIB", 5);
/* Use the function to retrieve some data into uda_area. */
QXXRTVDA(dtaname,START,LENGTH,uda_area);
/* Print the contents of the retrieved subset. */
printf("uda_area contains %7.7s\n",uda_area);
}
Hope this helps somebody not to waste time on such a basic thing.

Answer 2

The null-termation byte is only used to initialize the array if there is room for it.
#include <xxdtaa.h>
main()
{
_DTAA_NAME_T dtaara = {"ABCDEFGHIJ", "KLMNOPQRST"};
return;
}
In debug:
EVAL dtaara:x 20
00000 C1C2C3C4 C5C6C7C8 C9D1D2D3 D4D5D6D7 - ABCDEFGHIJKLMNOP
00010 D8D9E2E3 ........ ........ ........ - QRST............