NAME
bit, bool, short, int, unsiged - syntax for declaring and initializing variables of predefined integer data types.

SYNTAX
typename name [ = anyexpr ] [ , name [ = anyexpr ] ]*

unsigned name : constant

DESCRIPTION
There are six predefined integer data types: bit , bool , byte , short , int , and unsigned . (There are also constructors for user-defined data types, see mtype(2), and typedef(2), and a predefined data type for message passing channels, see chan(2).)

Variables of the predefined types can be declared in a C-like style, with a typename that is followed by a comma-separated list of one or more identifier names, each optionally followed by an initializer field. Each variable can also optionally be declared as an array, rather than as a scalar (for this see arrays(2)).

The integer data types differ only in the domain of values that a variable of the corresponding type can access. The precise domain can be system dependent in the same way that the corresponding data types in the language C can be system dependent. The dependencies are as follows.

Variables of type bit , and bool are stored in a single bit of memory, which means that they can hold only binary (Boolean) values (zero or one, or equivalently true or false ).

Variables of type byte are stored in a C variable of type unsigned char, which means on most systems that they can at least hold any positive value in the interval 0..255.

Variables of type short are stored in a C variable of type short, which means on most systems that they can at least hold values in the interval -2^15 -1..2^15 -1.

Variables of type int are stored in a C variable of type int , which means on most systems that they can hold values in the interval -2^31 -1..2^31 -1.

Variables of type unsigned are stored in a bit-field of a size that is specified in the constant that is given as part of the declaration.

ISO compliant implementations of C define the precise domains of the first five integer data types in the required header file limits.h .

The table below summarizes these definitions.

Typename bit or bool byte short int

C-equivalent bit-field uchar short int

Macro in limits.h - CHAR_BIT (width in bits) SHRT_MIN..SHRT_MAX INT_MIN..INT_MAX

Typical Range 0..1 0..255 -2^15 - 1 .. 2^15 - 1 -2^31 - 1 .. 2^31 - 1

The default initial value of all variables (declared globally or locally) is zero.

If a value is assigned that lies outside the domain of the variable type, the true value assigned is obtained by truncation of the value to the domain (i.e., by a type cast operation).

EXAMPLES
For instance,

byte a, b = 2; short c[3] = 3;