INFINITY
Section: Linux Programmer's Manual (3)
Updated: 20041031
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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 ("notanumber") that does not raise exceptions
when it is used in arithmetic. The opposite is a
signalling
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.
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.
CONFORMING TO
C99
SEE ALSO
fpclassify(3)
Index
 NAME

 SYNOPSIS

 DESCRIPTION

 AVAILABILITY

 CONFORMING TO

 SEE ALSO

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