HP C/iX Reference Manual (31506-90011)

146 Chapter9

HP C/iX Implementation Topics

Data Types

Data types are implemented in HP C/iX as follows:

• The char type is signed.

• All types can have the register storage class, although it is only honored for scalar

types. Ten register declarations per function are honored. More are honored when the

+R option is used.

• The signed integer types are represented internally using twos complement form.

• Structures (and unions) start and end on the alignment boundary of their most

restrictive member.

Table 9-1 lists the sizes and ranges of different HP C/iX data types.

Refer to the

HP C Programmer's Guide

for comparisons of data storage and alignment on

the following computer systems:

• HP 3000 Series 900

• HP 3000/V

• HP 9000 Series 300/400

• HP 9000 Series 700/800

Table 9-1. HP C/iX Data Types

Type Bits Bytes Low Bound High Bound Comments

char 8 1 -128 127 Character

signed char 8 1 -128 127 Signed integer

unsigned char 8 1 0 255 Unsigned integer

short 16 2 -32,768 32,767 Signed integer

unsigned

short

16 2 0 65,535 Unsigned integer

int 32 4 -2,147,483,648 2,147,483,647 Signed integer

unsigned int 32 4 0 4,294,967,295 Unsigned integer

long 32 4 -2,147,483,648 2,147,483,647 Signed integer

unsigned long 32 4 0 4,294,967,295 Unsigned integer

float 32 4 See (a) below. See (b) below. Floating-point

double 64 8 See (c) below. See (d) below. Floating-point

long double 128 16 See (e) below. See (f) below. Floating-point

enum 32 4 -2,147,483,648 2,147,483,647 Signed integer