INFINITY(3) Linux Programmers Manual INFINITY(3)
NAME
INFINITY, NAN, HUGE_VAL, HUGE_VALF, HUGE_VALL  floatingpoint con
stants
SYNOPSIS
#define _ISOC99_SOURCE
#include
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 ("notanumber") that does not
raise exceptions when it is used in arithmetic. The opposite is a sig
naling 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. Availabil
ity of the NAN macro can be tested using #ifdef NAN, and similarly for
INFINITY, HUGE_VALF, HUGE_VALL. They will be defined by 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), math_error(7)
COLOPHON
This page is part of release 3.05 of the Linux manpages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/manpages/.
20070726 INFINITY(3)
