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NAME | SYNOPSIS | DESCRIPTION | CONFORMING TO | AVAILABILITY | SEE ALSO | COLOPHON |
INFINITY(3) Linux Programmer's Manual INFINITY(3)
INFINITY, NAN, HUGE_VAL, HUGE_VALF, HUGE_VALL - floating-point con‐
stants
#define _ISOC99_SOURCE /* See feature_test_macros(7) */
#include <math.h>
INFINITY
NAN
HUGE_VAL
HUGE_VALF
HUGE_VALL
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.
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.
fpclassify(3), math_error(7)
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2007-07-26 INFINITY(3)
Pages that refer to this page: fpclassify(3), math_error(7)