Extended Unix Code

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Extended Unix Code (EUC) is a multibyte character encoding system used primarily for Japanese, Korean, and simplified Chinese (characters).

The most commonly used EUC codes are variable-length encodings with a character belonging to an ISO/IEC 646 compliant coded character set (such as ASCII) taking one byte, and a character belonging to a 94×94 coded character set (such as GB 2312) represented in two bytes. The EUC-CN form of GB 2312 and EUC-KR are examples of such two-byte EUC codes. EUC-JP includes characters represented by up to three bytes, including an initial shift code, whereas a single character in EUC-TW can take up to four bytes.

Modern applications are more likely to use UTF-8, which supports all of the glyphs of the EUC codes, and more, and is generally more portable with fewer vendor deviations and errors. EUC is however still very popular, especially EUC-KR for South Korea.