NAME¶
INFINITY, NAN, HUGE_VAL, HUGE_VALF, HUGE_VALL - floating-point constants
SYNOPSIS¶
#define _ISOC99_SOURCE /* See feature_test_macros(7) */
#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 positive
infinity.
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),
math_error(7)
COLOPHON¶
This page is part of release 3.74 of the Linux
man-pages project. A
description of the project, information about reporting bugs, and the latest
version of this page, can be found at
http://www.kernel.org/doc/man-pages/.
