HP C A.06.05 Reference Manual

Preprocessing Directives
Trigraph Sequences
Chapter 7 203
Trigraph Sequences
The C source code character set is a superset of the ISO 646-1983 Invariant Code Set. To
enable programs to be represented in the reduced set, trigraph sequences are defined to
represent those characters not in the reduced set. A trigraph is a three character sequence
that is replaced by a corresponding single character. Table 7-2 gives the complete list of
trigraph sequences and their replacement characters.
Any ? that does not begin one of the trigraphs listed above is not changed.
-notrigraph Option
In the ANSI extended (-Ae) mode, trigraph translation is automatically done. The option,
-notrigraph will disable automatic translation of trigraph sequences.
Table 7-2 Trigraph Sequences and Replacement Characters
Trigraph Sequence Replacement
??= #
??/ \
??' ^
??( [
??) ]
??! |
??< {
??> }
??-~