X07 Chapter Introduction : NAG Library, Mark 28

Modern systems allow you to control what happens to your program when an exceptional event such as overflow or division by zero occurs. Often, the default behaviour is for program execution to continue, while setting an appropriate flag. Sometimes the default behaviour is to halt execution and print a warning or error message.

The routines in Chapter X07 allow creation and detection of NaNs (Not a Number) and infinities, as well as alteration of the behaviour of a program when an exception occurs.

3 Recommendations on Choice and Use of Available Routines

Routines are provided to detect and create IEEE NaN (Not a Number) and infinity values, and to get and set the halting mode of various floating-point exceptions.

4 Functionality Index

Create a floating-point infinity

x07baf

Create a floating-point NaN (Not a Number)

x07bbf

Determine whether a floating-point number is finite

x07aaf

Determine whether a floating-point number is NaN (Not a Number)

x07abf

Get current behaviour of floating-point exceptions

x07caf

Set behaviour of floating-point exceptions