Functions
Special Quantifies.

Functions to detect and fabricate special quantities in floating-point numbers. More...

Functions

TRIO_PUBLIC_NAN int trio_isnan (double number)
 Check for NaN. More...
 
TRIO_PUBLIC_NAN int trio_isinf (double number)
 Check for infinity. More...
 
TRIO_PUBLIC_NAN int trio_isfinite (double number)
 Check for finity. More...
 
TRIO_PUBLIC_NAN int trio_signbit (double number)
 Examine the sign of a number. More...
 
TRIO_PUBLIC_NAN int trio_fpclassify (double number)
 Examine the class of a number. More...
 
TRIO_PUBLIC_NAN double trio_nzero (void)
 Generate negative zero. More...
 
TRIO_PUBLIC_NAN double trio_pinf (void)
 Generate positive infinity. More...
 
TRIO_PUBLIC_NAN double trio_ninf (void)
 Generate negative infinity. More...
 
TRIO_PUBLIC_NAN double trio_nan (void)
 Generate NaN. More...
 

Detailed Description

Functions to detect and fabricate special quantities in floating-point numbers.

SYNOPSIS

cc ... -ltrio -lm

#include <trionan.h>

DESCRIPTION

Certain arithmetical operations does not result in normal numbers. Instead they result in special quantities that must be handled differently by the floating-point hardware. These includes Infinity and Not-A-Number (NaN).

For example, 0/0 (zero divided by zero) yields NaN. Any operation which involves a NaN will result in NaN. Any comparison involving NaN will be unsuccessful, even if NaN is compared to NaN.

These special quantities are represented with special bit patterns by the floating-point hardware, and this bit patterns depend on the hardware. There may even be hardware that does not support special quantities, so the functions in this module are not guaranteed to work on all platforms.

The approach used in this module is to (in decreasing order of importance)

NOTES

This module does not depend on the rest of trio, and can thus be reused separately. The following files are necessary:

Function Documentation

TRIO_PUBLIC_NAN int trio_fpclassify ( double  number)

Examine the class of a number.

Parameters
numberAn arbitrary floating-point number.
Returns
Enumerable value indicating the class of number
TRIO_PUBLIC_NAN int trio_isfinite ( double  number)

Check for finity.

Parameters
numberAn arbitrary floating-point number.
Returns
Boolean value indicating whether or not the number is a finite.
TRIO_PUBLIC_NAN int trio_isinf ( double  number)

Check for infinity.

Parameters
numberAn arbitrary floating-point number.
Returns
1 if positive infinity, -1 if negative infinity, 0 otherwise.
TRIO_PUBLIC_NAN int trio_isnan ( double  number)

Check for NaN.

Parameters
numberAn arbitrary floating-point number.
Returns
Boolean value indicating whether or not the number is a NaN.
TRIO_PUBLIC_NAN double trio_nan ( void  )

Generate NaN.

Returns
Floating-point representation of NaN.

References trio_pinf().

TRIO_PUBLIC_NAN double trio_ninf ( void  )

Generate negative infinity.

Returns
Floating-point value of negative infinity.

References trio_pinf().

TRIO_PUBLIC_NAN double trio_nzero ( void  )

Generate negative zero.

Returns
Floating-point representation of negative zero.
TRIO_PUBLIC_NAN double trio_pinf ( void  )

Generate positive infinity.

Returns
Floating-point representation of positive infinity.

Referenced by trio_nan(), and trio_ninf().

TRIO_PUBLIC_NAN int trio_signbit ( double  number)

Examine the sign of a number.

Parameters
numberAn arbitrary floating-point number.
Returns
Boolean value indicating whether or not the number has the sign bit set (i.e. is negative).