INDEX

NAME, SYNOPSIS, DESCRIPTION, CONFORMING TO, AVAILABILITY, SEE ALSO, COLOPHON

INFINITY 3 2007-07-26 "" "Linux Programmer's Manual"

NAME

INFINITY, NAN, HUGE_VAL, HUGE_VALF, HUGE_VALL - floating point constants

SYNOPSIS

#define _ISOC99_SOURCE 


#include <math.h> 
INFINITY 
NAN 
HUGE_VAL 


HUGE_VALF 


HUGE_VALL 

DESCRIPTION

The macro INFINITY expands to a float constant representing positive infinity.

The macro NAN expands to a float constant representing a quiet NaN (when supported). A quiet NaN is a NaN ("not-a-number") that does not raise exceptions when it is used in arithmetic. The opposite is a signaling NaN. See IEC 60559:1989.

The macros HUGE_VAL , HUGE_VALF , HUGE_VALL expand to constants of types double, float and long double, respectively, that represent a large positive value, possibly plus infinity.

CONFORMING TO

C99

AVAILABILITY

On a glibc system, the macro HUGE_VAL is always available. Availability of the NAN macro can be tested using "#ifdef NAN" , and similarly for INFINITY , HUGE_VALF , HUGE_VALL . They will be defined by <math.h> if _ISOC99_SOURCE or _GNU_SOURCE is defined, or __STDC_VERSION__ is defined and has a value not less than 199901L.

SEE ALSO

fpclassify(3), feature_test_macros(7)

COLOPHON

This page is part of release 2.79 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.

Possibly related

raw nroff source of INFINITY(3)