COBOL words with single-byte characters

A COBOL word is a character-string that forms a user-defined word, a system-name, or a reserved word. The maximum size of a COBOL user-defined word is 30 bytes. The number of characters that can be specified depends on the code page indicated by the compile-time locale.

Except for arithmetic operators and relation characters, each character of a COBOL word is selected from the following set:

  • Latin uppercase letters A through Z
  • Latin lowercase letters a through z
  • digits 0 through 9
  • - (hyphen)
  • _ (underscore)

The hyphen cannot appear as the first or last character in such words. The underscore cannot appear as the first character in such words. Most user-defined words (all except section-names, paragraph-names, priority-numbers, and level-numbers) must contain at least one alphabetic character. Priority numbers and level numbers need not be unique; a given specification of a priority-number or level-number can be identical to any other priority-number or level-number.

In COBOL words (but not in the content of alphanumeric, DBCS, national, and UTF-8 literals), each lowercase single-byte alphabetic letter is considered to be equivalent to its corresponding single-byte uppercase alphabetic letter.

The following rules apply for all COBOL words:

  • A reserved word cannot be used as a user-defined word or as a system-name.
  • The same COBOL word, however, can be used as both a user-defined word and as a system-name. The classification of a specific occurrence of a COBOL word is determined by the context of the clause or phrase in which it occurs.