IBM AS/400 Data, Displaying Variable-Length Fields, by Pointers, Displaying Null-Capable Fields

Stepping Through the Program Object

Displaying		UCS-2		Data
The	value		displayed		for	UCS-2	fields has	been	translated	into	readab
For	example,			if a UCS-2 field			has been	set to	%UCS2('abcde'),		then t
played for				that field would			be 'abcde'. You can display			UCS-2 data
using		the	:u	suffix	for	EVAL.

Displaying Variable-Length Fields

When you use EVAL fldname for

a

variable

length

field,

only the

data

field is shown. When you use

any

suffix

such

as

:c

or

:x

for

the

including the length is shown.

To

determine

the

current

length

of

a

va

field, use EVAL fldname:x. The

length is the first four

hexadecimal

d

format.

You must

convert this

value

to decimal

form

to

get

the length;

if the

result is

003DF1F2...,

the

length

is 003D

which

is

(3

*

16)

+

Displaying Data			Addressed	by Pointers
If	you	want	to see	what	a pointer is pointing to, you can use the
with	the	:c	or :x suffix. For example, if pointer field PTR1 is poin
character		data,
EVAL PTR1:c 10
will	show	the	contents	of	those 10 bytes.

You can also show the contents in hexadecimal using:

EVAL PTR1:x 10

This would be especially useful when the data that the pointer addre stored in printable form, such as packed or binary data.

Displaying Null-Capable Fields

You

can

use

the

EVAL debug command to display the null indicator

of

a

capable field. The null indicator

is

an internal

variable

(similar

to

th

for multiple-occurrence DS) which is named _QRNU_NULL_fieldname. The

fieldname can be

the

name

of

an

array

if the

array

is

null-capable.

When the debugger displays a

null-capable field, the content

of

the

played

regardless

of

whether

the

field

is

considered

null.

For

exampl

FLD1

is

null-capable,

and

is

currently

null.

Then

the result

of

EVAL

_QRNU_NULL_FLD1 is

'1'

and

EVAL

FLD1

shows

the

current content

of

FLD1,

even

though

its null

indicator

is on.

EVAL _QRNU_NULL_FLD1

Result:

_QRNU_NULL_FLD1 = '1'

EVAL FLD1

Result:

FLD1 = 'abcde'

Using	Debug Built-In Functions
The	following built-in	functions are		available	while	using the ILE source
%SUBSTR
	Substring a	string	field.
%ADDR	Retrieve the address of a field.
%INDEX	Change the index of a table or multiple-occurrence data struct
%VARS	Identifies	the	specified	parameter	as	a variable.

206 ILE RPG for AS/400 Programmer's Guide