36.2.2 Syntax Flags

In addition to the classes, entries for characters in a syntax table can specify flags. There are eight possible flags, represented by the characters ‘1’, ‘2’, ‘3’, ‘4’, ‘b’, ‘c’, ‘n’, and ‘p’.

All the flags except ‘p’ are used to describe comment delimiters. The digit flags are used for comment delimiters made up of 2 characters. They indicate that a character can also be part of a comment sequence, in addition to the syntactic properties associated with its character class. The flags are independent of the class and each other for the sake of characters such as ‘*’ in C mode, which is a punctuation character, and the second character of a start-of-comment sequence (‘/*’), and the first character of an end-of-comment sequence (‘*/’). The flags ‘b’, ‘c’, and ‘n’ are used to qualify the corresponding comment delimiter.

Here is a table of the possible flags for a character c, and what they mean: