INFINITY, NAN, HUGE_VAL, HUGE_VALF, HUGE_VALL — floating-point constants
#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 plus infinity.
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.
This page is part of release 3.33 of the Linux man-pages project. A
description of the project, and information about reporting
bugs, can be found at http://man7.org/linux/man-pages/.
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Copyright 2004 Andries Brouwer <aebcwi.nl>. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. |