Text that is set to a size of 9 pt in the Simsun-18030 font is displayed incorrectly on a computer that is running Windows XP or Windows 2000

Consider the following scenario:

• You have a computer that is running Windows XP or Windows 2000.
• On this computer, you set the size of text in a program to 9 pt in the Simsun-18030 font.

In this scenario, the text is displayed incorrectly on the screen.

Hotfix information

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that is described in this article. Apply it only to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Windows XP service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Customer Support Services to obtain the hotfix. For a complete list of Microsoft Customer Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.
Note There is no service pack release scheduled for Windows 2000.

Prerequisites

You must install the GB18030 support package before you apply this hotfix. To download this support package, visit the following Microsoft Web site.
The following file is available for download from the Microsoft Download Center:
Download the GB18030 support package now. (http://www.microsoft.com/downloads/details.aspx?FamilyID=fc02e2e3-14bb-46c1-afee-3732d6249647&DisplayLang=en)

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

GB18030 character encoding standard

The Simsun-18030 font implements the GB18030 Chinese character encoding standard. This standard contains many characters, and it includes some difficult new compliance requirements. GB18030-2000 encodes characters in sequences of 1, 2, or 4 bytes. These sequences are defined as follows.

Single-byte sequence

The single-byte sequence uses the code points 00 to 0x7f: The single-byte sequence applies the standard GB 11383 coding structure and principles. GB 11383 is identical to ISO 4873:1986.

Double-byte sequence

The double-byte sequence uses the following 8-bit sequences: The double-byte sequence uses two 8-bit sequences. This resembles the behavior of most double-byte character sets. The leading-byte code points range from 0x81 through 0xfe. The trailing-byte code points range from 0x40 through 0x7e and from 0x80 through 0xfe. The double-byte sequence has the same problem as most double-byte character sets. Because some code points may consist of either a leading or trailing byte, this makes character delimitation a very complex process.

4-byte sequence

The 4-byte sequence uses the code points 0x30 through 0x39 as a way to extend double-byte encodings. This means that the 4-byte code points range from 0x81308130 through 0xfe39fe39.

Why the GB18030 encoding standard is unusual

• The GB18030 standard includes as many as 1.6 million characters. This is a larger number of characters than in any other Windows-supported code page (Unicode included).
• GB18030 characters can be 1, 2, or 4 bytes. Windows has never supported a 4-byte code page before, and many system interfaces and data structures do not work with 4-byte characters. Moreover, it is impossible to tell from a particular byte whether it is the first, second, third, or fourth byte of a character. This makes processing more difficult than for other code pages.
• Products sold in China must comply with this standard. The Chinese government defines and determines compliance.
• GB18030 compliance includes requirements to support some previously unsupported languages. For example, Tibetan, Mongolian, Yi, and Uyghur must be supported in a GB18030-compliant environment.

For more information about GB18030 encoding, visit the following Microsoft Web site: