Quick start manual

Memory management

11-3

Internal data formats

The following sections describe the internal formats of Delphi data types.

Integer types

The format of an integer-type variable depends on its minimum and maximum

bounds.

• If both bounds are within the range –128..127 (Shortint), the variable is stored as a

signed byte.

• If both bounds are within the range 0..255 (Byte), the variable is stored as an

unsigned byte.

• If both bounds are within the range –32768..32767 (Smallint), the variable is stored

as a signed word.

• If both bounds are within the range 0..65535 (Word), the variable is stored as an

unsigned word.

• If both bounds are within the range –2147483648..2147483647 (Longint), the

variable is stored as a signed double word.

• If both bounds are within the range 0..4294967295 (Longword), the variable is

stored as an unsigned double word.

• Otherwise, the variable is stored as a signed quadruple word (Int64).

Character types

A Char, an AnsiChar, or a subrange of a Char type is stored as an unsigned byte. A

WideChar is stored as an unsigned word.

Boolean types

A Boolean type is stored as a Byte, a ByteBool is stored as a Byte, a WordBool type is

stored as a Word, and a LongBool is stored as a Longint.

A Boolean can assume the values 0 (False) and 1 (True). ByteBool, WordBool, and

LongBool types can assume the values 0 (False) or nonzero (True).

Enumerated types

An enumerated type is stored as an unsigned byte if the enumeration has no more

than 256 values and the type was declared in the {$Z1} state (the default). If an

enumerated type has more than 256 values, or if the type was declared in the {$Z2}

state, it is stored as an unsigned word. If an enumerated type is declared in the {$Z4}

state, it is stored as an unsigned double-word.