This document is only relevant for Asian countries which use double-byte character sets. It describes all features implemented in Natural to support DBCS terminals and printers. It covers the following topics:
In alphanumeric fields with SBCS and DBCS characters mixed, the DBCS character strings are separated from the SBCS strings by shift codes called SO (shift-out) and SI (shift-in). The Natural profile parameter SOSI is used to pass the values of the shift-in and shift-out codes used in the current environment to Natural.
It is strongly recommended to use the IBM characters X'0E'
and X'0F' internally. With this technique, all applications and
data can be handled in a compatible manner, which means that a network
supporting different mainframe types can still use the same Natural
applications and process the same data.
For detailed information on this parameter, see
SOSI.
The Natural session parameter PM=D is used to define
DBCS-only fields. A DBCS-only field must contain only valid DBCS characters;
shift-out/shift-in characters (SO/SI) are not allowed within such a field. To
display a field with the session parameter PM=D specified, the
screen attribute X'43F8' is added for IBM terminals; for Fujitsu
terminals, the field content is enclosed in the required shift-out/shift-in
characters (SO/SI).
The following parameters must be specified in the setup for Natural for the support of double-byte character sets:
| Parameter | Explanation |
|---|---|
TS=ON
|
If Latin lower-case characters are not available, this parameter
translates all Natural system output using the translation table defined by the
macro NTTABL in the NATCONFG
module.
|
SOSI=(0E,0E,0F,0F,1) |
Defines the DBCS shift-out and shift-in values for IBM hardware. |
SOSI=(28,28,29,29,0)
|
Defines the DBCS shift-out and shift-in values for Fujitsu hardware. |
LC=ON
|
Does not translate all input data to uppercase, which again would destroy possible DBCS input data. |
In addition to TS=ON, further parameters to provide for
translation of messages into upper case are provided by several Natural
components. For detailed information, see
Other Parameters to
Provide Upper Case Translation in the
TS profile
parameter documentation.
If you want to enter DBCS or half-width Katakana characters in one of the Natural editors, the following editor general default options should be set in the editor profile to avoid that character constants or field names containing DBCS or half-width Katakana characters are unintentionally converted to upper case:
| Option | Value | Explanation |
|---|---|---|
| Editing in Lower Case | Y |
Lower-case characters in the source code are not automatically converted to upper case. This option is required if you are using DBCS or half-width Katakana characters. |
| Dynamic Conversion of Lower Case | N |
Any source code remains as you enter it. This option is required if you are using half-width Katakana characters. |
For detailed information on the editor general default options, see
General
Defaults. For detailed information on the editor profile,
see Editor
Profile in the Editors documentation.
To avoid the need to change these options for every user, you can modify the
default profile for your installation by means of the user exit routine
USR0070P, which also supports DBCS; see
USR0070P - User Exit for
Editor Profiles in the section Configuring
Natural.
If the session parameter PM=D is set for a field,
it is verified that the input data
contains an even number of bytes,
contains only valid DBCS characters,
does not contain shift-out/shift-in characters (SO/SI).
Because the detection of non-DBCS characters requires
ICU, this check will not
be performed if ICU is not available (that is, if the profile parameter
CFICU=OFF has been set).
If a window is to be displayed for user interaction, the window might
overlay DBCS characters that are already displayed, or the window might itself
contain DBCS characters which are truncated because of the window size. An
overlay may also occur if the NO ERASE option is used with an
INPUT statement. In order to prevent screen corruption in case of
such an overlay, the following actions are performed to adjust the output data,
if necessary:
if the session parameter PM=D is set for a field, an
orphan byte (that is, a single byte left at the beginning or end of the data to
be displayed as a result of a partial overlay of a DBCS character) is replaced
by an attribute; this operation assures that only valid DBCS characters are
displayed;
if the profile parameter SOSI has been set, the field
contents of an alphanumeric field for which PM=D is not specified
is examined for shift-out/shift-in characters (SO/SI); if a shift-out character
(SO) is found for which the correlating shift-in character (SI) is missing,
either the last character of the output data is replaced by a shift-in
character (SI) or the last two characters are replaced by a shift-in character
(SI) followed by a blank; if a shift-in character (SI) is found for which the
correlating shift-out character (SO) is missing, either the first character of
the output data is replaced by a shift-out character (SO) or the leading two
characters are replaced by a blank followed by a shift-out character (SO); this
operation assures that DBCS characters are enclosed properly by
shift-out/shift-in characters (SO/SI).
To avoid unintentional interpretation of DBCS characters as delimiter or
control characters, the FORMATTED option of the
STACK statement should
be used if the data to be placed on the Natural stack contains DBCS
characters.
See the Statements documentation for further
information on the STACK statement.
See the Programming Guide for further information on the Natural Stack.
The following user application programming interfaces (API) are available to support DBCS handling:
These APIs are contained as subprograms in the Natural library
SYSEXT. Detailed information on how to use an API is included in
the corresponding text object (USRxxxxT). See also
SYSEXT Utility - Natural
Application Programming Interfaces in the
Utilities documentation.
The application programming interface USR4211N can be used
to obtain information on the availability of DBCS support and the defined SOSI
characters.
The application programming interface USR4213N can be used
to perform the following functions:
Convert a normal Latin character string into the corresponding DBCS character string.
Convert a DBCS character string that contains Latin data only into a single-byte character string.
Add the current shift codes at the beginning and at the end of a character string.
Remove leading and trailing shift codes from a character string.
The last two functions can be used to either produce native DBCS strings or generate mixed-mode data out of native DBCS strings.
The alternate text module NATTXT2U contains certain
keywords for English language in all upper case which are contained in mixed
case in text module NATTXT2. NATTXT2U should be
linked to the Natural nucleus instead of NATTXT2 in environments
where lower case code points H'81' to H'A9' are used
to display national characters.