The following lists the basic source character sets that
are available at both compile time and run time:
- The uppercase and lowercase letters of the English alphabet:
a b c d e f g h i j k l m n o p q r s t u v w x y z
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
- The decimal digits:
0 1 2 3 4 5 6 7 8 9
- The following graphic characters:
! " # % & ' ( ) * + , - . / : ; < = > ? [ \ ] _ { } ~
- The caret (‸) character in ASCII (bitwise exclusive OR symbol).
- The split vertical bar character in ASCII.
- The space character
- The control characters representing new-line, horizontal tab, vertical tab, form feed, end of string (NULL character), alert, backspace, and carriage return.
Depending
on the compiler option, other specialized identifiers, such as the
dollar sign ($) or characters in national character sets, may be allowed
to appear in an identifier.