Chapter 5 Manager Overview

LabVIEW block diagrams store Boolean scalars as 16-bit values. The high-bit is set if the Boolean is TRUE, and clear if the Boolean is FALSE. This form of Boolean is called an LVBoolean.

The two forms of Booleans are summarized in the following table.

Name	Description
Bool32	32-bit integer, 1 if TRUE, 0 if FALSE
LVBoolean	16-bit integer, high-bit set if TRUE, clear if FALSE

Numerics

The managers support 8-, 16-, and 32-bit signed and unsigned integers. For floating-point numbers, LabVIEW supports the single (32-bit), double (64-bit), and extended floating-point (at least 80-bit) data types. LabVIEW supports complex numbers that contain two floating-point numbers, with different complex numeric types for each of the floating-point data types. The following lists show the basic LabVIEW data types for numbers.

•Signed Integers

–	int8	8-bit integer
–	int16	16-bit integer
–	int32	32-bit integer

•Unsigned Integers

– uInt8

8-bit unsigned integer

–uInt16 16-bit unsigned integer

–uInt32 32-bit unsigned integer

•Floating-Point Numbers

–float32 32-bit floating-point number

–float64 64-bit floating-point number

–floatExt extended-precision floating-point number

In Windows, extended-precision numbers are stored as an 80-bit structure with two int32 components, mhi and mlo, and an int16 component, e. On the Sun, extended-precision numbers are stored as 128-bit floating-point numbers. On the 68K Macintosh, extended-precision numbers are stored in the 96-bit MC68881 format.

© National Instruments Corporation

5-3

LabVIEW Code Interface Reference Manual