Process double-byte characters

Due to the large number of double-byte characters, the system needs more information to identify each double-byte character than is needed to identify each alphanumeric character.

There are two types of double-byte characters: basic and extended. These characters are typically processed by the device on which the characters are displayed or printed.

Basic double-byte characters:

Basic characters are frequently used double-byte characters that reside in the hardware of a DBCS-capable device. The number of double-byte characters stored in the device varies with the language supported and the storage size of the device. A DBCS-capable device can display or print basic characters without using the extended character processing function of the operating system.

Double-byte extended characters:

When processing extended characters, the device requires the assistance of the system. The system must tell the device what the character looks like before the device can display or print the character. Extended characters are stored in a DBCS font table, not in the DBCS-capable device. When displaying or printing extended characters, the device receives them from the DBCS font table under control of the operating system.

Extended character processing is a function of the operating system that is required to make characters stored in a DBCS font table available to a DBCS-capable device.

To request extended character processing, specify the double-byte extended character parameter, IGCEXNCHR(*YES), on the file creation command when you create a display (CRTDSPF) or create a printer file (CRTPRTF) command that processes double-byte data. Because IGCEXNCHR(*YES) is the default value, the system automatically processes extended characters unless you instruct it otherwise. You can change this file attribute by using the change file (CHGDSPF) or (CHGPRTF) command. You can override the file attribute with the override display file (OVRDSPF) or override printerfile (OVRPRTF) command. For example, to override the display file DBCSDSPF so that extended characters are processed, enter:

OVRDSPF DSPF(DBCSDSPF) IGCEXNCHR(*YES)

Notes:

The system ignores the IGCEXNCHR parameter when processing alphanumeric files.
When you use the Japanese 5583 Printer to print extended characters, you must use the Kanji print function of the Advanced DBCS Printer Support licensed program.

What happens when extended characters are not processed:

When extended characters are not processed, the following events happen:

Basic double-byte characters are displayed and printed.
On displays, the system displays the undefined character where it would otherwise display extended characters.
On printed output, the system prints the undefined character where it would otherwise print extended characters.
The extended characters, though not displayed or printed, are stored correctly in the system.