HP Fortran Programmer's Reference (September 2007)

Data types and data objects

Intrinsic data types

Chapter 5 107

Intrinsic data types

The intrinsic data types are the data types predeﬁned by the HP Fortran language, in

contrast with derived types, which are user-deﬁned (see “Derived types” on page 123). The

intrinsic data types include numeric types:

• Integer

• Real

• Complex

and nonnumeric types:

• Character

• Logical

Each type allows the speciﬁcation of a kind parameter to select a data representation for that

type (see “Type declaration for intrinsic types” on page 109 for the format of the kind

parameter). If the kind parameter is not speciﬁed, each type has a default data

representation. Table 5-1 identiﬁes the data representation for each type, including the

default case where a kind parameter is not speciﬁed. The types are listed by keyword and

applicable kind parameter. The table also includes the data representation for the HP

extensions, BYTE and DOUBLE COMPLEX.

As shown in Table 5-1, HP Fortran aligns data on natural boundaries. Entities of the intrinsic

data types are aligned in memory on byte boundaries of 1, 2, 4, or 8, depending on their size.

Array variables are aligned on an address that is a multiple of the alignment required for the

scalar variable with the same type and kind parameters.

NOTE The ASCII character set uses only the values 0 to 127 (7 bits), but the

HP Fortran implementation allows use of all 8 bits of a character entity. The

processing of character sets requiring multibyte representation for each

character makes use of all 8 bits.

For additional information about data representation models, see “Data representation

models” on page 507.

Table 5-1 Intrinsic data types

Type Range of values

Precision (in

decimal digits)

Bytes Alignment