 INFINITY(3)  phpMan
INFINITY(3) Linux Programmer's Manual INFINITY(3)
NAME
INFINITY, NAN, HUGE_VAL, HUGE_VALF, HUGE_VALL  floatingpoint 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 ("notanumber") 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 infin‐
ity.
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_VER‐
SION__ 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 manpages 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/manpages/.
20070726 INFINITY(3)
