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-num-
       ber") 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 3.25 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)