Character sets and identifiers

Uppercase and lowercase characters are distinct in all internal and external identifiers. An identifier can also contain a dollar ($) character unless the --strict compiler option is specified. To permit dollar signs in identifiers with the --strict option, also use the --dollar command-line option.

Calling setlocale(LC_CTYPE, "ISO8859-1") makes the isupper() and islower() functions behave as expected over the full 8-bit Latin-1 alphabet, rather than over the 7-bit ASCII subset. The locale must be selected at link time.

Source files are compiled according to the currently selected locale. You might have to select a different locale, with the --locale command-line option, if the source file contains non-ASCII characters. See Compiler command-line options listed by group in Using the Compiler for more information.

The compiler supports multibyte character sets, such as Unicode.

Other properties of the source character set are host-specific.

The execution character set is identical to the source character set.

There are eight bits in a character in the execution character set.

There are four characters (bytes) in an int. If the memory system is:

In C all character constants have type int. In C++ a character constant containing one character has the type char and a character constant containing more than one character has the type int. Up to four characters of the constant are represented in the integer value. The last character in the constant occupies the lowest-order byte of the integer value. Up to three preceding characters are placed at higher-order bytes. Unused bytes are filled with the NULL (\0) character.

Table 31 lists all integer character constants, that contain a single character or character escape sequence, are represented in both the source and execution character sets.

Characters of the source character set in string literals and character constants map identically into the execution character set.

Data items of type char are unsigned by default. They can be explicitly declared as signed char or unsigned char:

No locale is used to convert multibyte characters into the corresponding wide characters for a wide character constant. This is not relevant to the generic implementation.