INFINITY(3)						     Linux Programmer's Manual						       INFINITY(3)

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 ("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.

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_VERSION__	is
       defined and has a value not less than 199901L.

SEE ALSO

       fpclassify(3), feature_test_macros(7), math_error(7)

COLOPHON

       This  page is part of release 3.27 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

								    2007-07-26							       INFINITY(3)