Restrictions on character sets using C and C++ to program embedded SQL applications

Some characters from the C or C++ character set are not available on all keyboards. You can enter these characters into a C or C++ source program by using a sequence of three characters called a trigraph. Trigraphs are not recognized in SQL statements.
The precompiler recognizes the following trigraphs within host variable declarations:
Trigraph
Definition
??(
Left bracket '['
??)
Right bracket ']'
??<
Left brace '{'
??>
Right brace '}'
The following trigraphs listed might occur elsewhere in a C or C++ source program:
Trigraph
Definition
??=
Hash mark '#'
??/
Back slash '\'
??'
Caret '^'
??!
Vertical Bar '|'
??-
Tilde '~'